I finally succeeded in paying for my T-Mobile prepaid service with a credit card online again. For several years now, I’ve been unable to pay online with my credit card, so I’ve had to buy the prepaid refill cards from the store on occasion. This of course required remembering when my balance was low with enough time to get to the store. The card I had been using was a Discover card, which had worked fine for years before that. Since my balance is due again and T-Mobile recently started requiring debit cards for post-paid plans, I decided to see if that would work fine for prepaid. It did. It hasn’t appeared on my balance yet, but I did get a confirmation code and saved the receipt just in case. They didn’t email me one so I had to download the PDF. Anyway, assuming no problems crop up, this will make it much easier to pay going forward.