I'm on Verizon; but I just wanted to confirm that Rootcloak works for me

Without rootcloak, I think Isis will still download; but it won't finish initializing on the first run.
Give AT*T a call and see if they need to flip a switch on your settings; you also might verify you have a NFC secure element SIM card.
Also, are you on a custom rom? If the build.prop file isn't correct, then it won't show in the Play Store (at least on Verizon). That is more important than having hiding Root. In my experience, a rooted phone will still show Isis in the Play Store, it just won't initialize properly once downloaded. If you aren't seeing it in the Play store, then something must be wrong with your ROM - maybe try a stock rom (and then add root and xposed/rootcloak after).
I got a $40 credit on a new American Express Serve card; and there's an Isis promo that give you $1 credit for each purchase over $1 for the next 3 months

My favorite stop in the morning is to get a Pepsi for $1.06 and they have a tap-to-pay reader
Needless to say, I switched from having Google Wallet as my default tap-to-pay program. I prefer Google Wallet; but the freebies are too good to pass up for now. I live in Utah and they have been running lots of good Isis freebies for the last year - I wish the light rail was still free

My phone was always rooted (HTC DNA) and before RootCloak, I only managed to get Isis working for about 2 weeks on that phone.