I tried to buy some credits at Secret Benefits but the banks (Visa) turned down both my debit and credit cards.   Yes, i have plenty of funds in the debit account and a platinum visa.

Depending on your bank's risk aversion policy and the type of accounts you have with them, they may be auto-declining any non-US transactions, or declining any "dating site" merchant types. If you call them, you MAY get them to reclassify your account to allow those transaction types. Or they may not.  You might have to open a separate account with a more "adult services friendly" policy...  

Tell them that you would like to make a charge to a particular account, and they'll run through all the normal security questions, etc.

I have my main account with one of the large national banks for about 40 years. My Visa is tied to my main bank. i do believe though that they tend to have more than one procedure that they employ. For TER for example they just approve each time the charge comes through. The first couple of times I had to go into the account and request their approval.  Now, for me, for all other apparently related sexual charges, they just put a hold on the payment until I go into the account and mark as really me. Process now takes about 3 minutes as, lol, they have me really trained to do what they want me to do.

I called my bank. Told them the vendor and dollar amount and it went through

Not only did the cards get declined, they locked out my debit and credit cards.  Had to wait through three different reps to get everything unblocked.