That's true of my LG Tribute HD's and Moto E phones, but my LG Volt can send/receive them with wifi. There was a thread on Social about this a while back:
https://social.ringplus.net/discussion/9958/mms-sms-group-text-with-data-off
Interesting. I did some tests using a Samsung Galaxy S4 on AT&T to exchange MMS picture messages with a LG G2 on Twigby. The S4 was connected to the cell network via LTE. I tried the following combinations of settings on the G2.
[ul]
[li]Mobile data off, wifi off: Not able to send or receive MMS[/li]
[li]Mobile data off, Wifi on: Able to send and receive MMS[/li]
[li]Airplane mode, Wifi on: Not able to send or receive MMS[/li]
[/ul]
So for MMS to work, it seems that you must have a cellular voice connection plus either wifi or cellular data connection. Wifi alone is not sufficient.
I ported over from R+ and the form didn't have a place for a referral code. I used chat to add the referral code and the rep said it was added but I don't see anything in my account to reflect this. Is there somewhere this should be showing or do I have to wait until the end of the month to see it?
This makes sense. When I was on R+ I had roaming enabled on my account but on my phone I had data roaming turned off. When I was roaming and someone sent a mms I would get an sms saying that that person send me a mms but it couldn't be retrieved. So it seems mms uses some component of sms along with data.
referral credits are posted after 30 days. Presumably to make sure you use them and not just sign uo get a freebie and leave.
I don't know if it would work any differently with AT&T, but it's definitely phone dependent, so I would not be surprised that the S4 doesn't do it. Of my phones, only the LG Volt (on Sprint network / MVNO's) could send/receive MMS with wifi while data was disabled on phone and account (for testing). My LG Tribute HDs and Moto E, however, must be connected to mobile data to use MMS. I wish they worked like my Volt.
Before going to RingPlus I had a Samsung Galaxy Exhibit 4G that I used on T-Mobile without a data plan. It could not do MMS since there was no data and it couldn't get MMS over wifi either. The text portion would download like normal SMS but the multimedia content would just show up as a black box in the text.
For those who don't know, Twigby does offer an app for Android or iOS which provides access to usage stats and account info.
The bad news is that it is very basic. It seems to just be a front end for the mobile web site. It also doesn't remember your login credentials for very long, so you have to re-login frequently.
I chatted with support and asked them if they had plans to provide a more full featured app, or an API for 3rd party apps. I also pointed them to RP Samara as an example of a good app. The support person didn't have any info about this, but offered to forward my inquiry to someone else. Who knows what will happen, we'll have to wait and see.
It anyone else is interested in a better app, it couldn't hurt to open a quick support chat and politely let them know. 
Anyone who is interested in how many referrals they have can pm twigby over at ringplus social apparently and they will provide details.
I ported to Tello, but I've moved some people to Twigby with what I believe is the ultimate cheapskate setup.
These are people who get good Sprint coverage but frequently find themselves in Verizon-only areas of rural Georgia.
$12 plan with 200 minutes, unlimited SMS, 150 MB LTE, unlimited throttled data. Talk and text roam on Verizon. (Data does not.)
Use Google Hangouts for unlimited Sprint network calling. (It works fine on throttled data.)
Use Google Voice for 200 minutes of Verizon network calling.
I've had a number of people get very excited about this economical setup. Just wanted to share, in case it hasn't already been discussed. (I didn't read the entire thread.)
Any idea what the throttle speed is?
64k
Just to let you guys know Twigby had to temporarily take down the ability to change plans to fix an issue. Should be back up by the end of the week. If you need to change your plan in the meantime just reach out to customer service.
https://social.ringplus.net/discussion/comment/150897/#Comment_150897
I've also invited them over here and they were receptive to the idea. So expect a twigby representative to be around sometimes to answer any questions in the near future.
Hi guys! Chris from Twigby here Thanks to @mmfacemm for the invite. I've also sent a message to hungryghost to get a verified badge for this account!
I think I've met many of you over at the R+ forum already, so I'm happy to be here to continue discussing Twigby with you all and answering any questions, etc. you may have!
How long will the R+ promo for a free month be running for?
Welcome!
It's still going! So far, no talks of a final date that the promo will be removed as we know there are still a lot of former r+ users looking for a final plan to rest on. If I hear of a final date for the promo, I'll be sure to post here!
There will be numerous people coming from Ting and looking for a new home after their credit runs out I imagine.
Another suggestion - let us use any referral credits to buy a new phone.
The throttled speed isn't too bad for mobile browsing/Facebook app/ email.
I tried connecting via tethering on my PC and it just won't cut it there.
Much slower than I like, but, at least I have access to the Internet even after my 4G is gone.