I've seen this kind of thing happen with other payment processors, by the way. It'll be one of two things:
1. The payment processor has a newly-appointed board member or executive who is American and/or religious right, and they've had a moral panic moment. Decide to cut out all "adult service" processors, usually without warning.
2. There have been an unusually high volume of chargebacks from credit card companies and it's now not profitable for the payment processor to continue with the account. (Adult services are frequently the victim of chargebacks due to two reasons: horny men who spend their money with their penis and then decide they didn't want to, and horny men who get found out by their wife/mum and claim their card was used fraudulently.)
I've seen scenario 1 before when I worked for a digital art site. Paypal suddenly got their knickers in a twist because there were artistic nudes on the site. (Well - not all of them could be classed as art, but it was nothing explicit.) We had to run around like fucking maniacs removing all the nude content and locking down everything so you had to verify age before you could see a nipple.