My account just dropped, inexplicably, by about $7 or $8.
I'm still on the free plan and the free plan is showing as scheduled to renew in 5 days.
I scanned back over my earnings list and I don't notice any changes, so I don't know where the reduction came from.
I checked my mother's account and it looks fine.
FreeUP giveth and FreeUP taketh away.
I would suggest screenshoting your earnings, from now on, like I'm going to start doing.
FreeUP's penchant for removing, adding and changing things in people's accounts without any explanation given is truly disconcerting and unacceptable, and they're hurting their chances of doing well because of it. For a while, I was taking screenshots, which is a hassle and shouldn't be needed, but stopped when FU became more consistent for me. I just bumped one account to the $15 plan because my coupon earnings have been very consistent. Yet I'm still treading on pins and needles anticipating another FreeUp sleight of hand snafu.
You have always been thoughtful and smart so I am sincerely asking: if we go through the effort of documenting (screenshots) what we collectively already know- what is our recourse?
I don't know if there's any actual recourse other than appealing to customer support, but documentation would be critical if one wanted to prove their case.
Still-- they could certainly ignore you.
FreeUP's benefits still outweigh the concerns, but they're keeping that closer to the tipping point than they should. 
@Isamorph.... I was thinking of bumping up to the $15 plan as well. Did you have to initially have to make a credit card payment to upgrade plans or were you able to use rewards to do it?
I had a similar incident last month when it dropped close to $2, overnight. I wrote to customer support about that and have not had a reply yet. I wrote both by using the form on their website and by reply to a customer service communication I had with them last fall.
I have been with them for nearly a year and the times I have heard back from them, it took several weeks to get a reply.
Thanks for your suggestion of screenshoting.
I have about $20 in rewards that will be used to pay the $15 due in two days. I was able to do the same when upgrading from the free plan to the $10 plan. The CC I used to purchase the original FU sim is still on file in my FreeUp account but hasn't been charged since purchasing the sim. So, it would appear if one has enough rewards to pay for the $15 plan, then no CC would be needed, and if rewards are insufficient to pay the full $15, then I assume FU would use all one's rewards and charge your CC the difference.