$5 auto-pay discount, T-Mobile's breach of contract

I agree this is a sneaky end-around move by an untrustworthy player in an untrustworthy industry. I'm not sure the exact basis of a class action suit although the spirit of the agreement was clearly breached. It's also interesting to me and I'm no expert but let's say the cost of taking a card is 3% then on my $40 bill, that would be $1.20 so how is it that they figure to take $5.00 from me? Why would anyone want to trust T-mobile with my private banking information that exposes me to losing the max balance in my checking account vs the $50 max exposure to a credit card? According to my conversation today with T-mobile, "most customers have provided their debit card information". First of all, I doubt that; I think most are just paying $5/mo more either because they don't want to divulge bank info or because they are too lazy to make the switch. Today I tried to switch to the debit card but was unable to do so because the T-mobile system is flawed that I couldn't even to that. After that, I called T-mobile and after an hour of voicing my disgust with T-mobile's dishonesty, I was given my $5/month AutoPay discount back forever using a card (or so they promised) but also given a $35 statement credit for my time. Pro tip: I specifically mentioned that it had cost me over an hour of my time to try to fix this problem. As usual, the Reps were super nice (not their fault, they don't own T-mobile). So I guess I said something nice about T-mobile (reps are super nice). This does not excuse T-mobile dishonesty and the millions ripped off by it but maybe leaves a path for those of us who are willing to fight to receive their just due.