Continued Issues with Buying a 1 Month Sub

So every month I buy a new sub, then a few days later I cancel it.

My finanical situation means that a recurring subscription isn’t realistic as sometimes I don’t have enough money in my account.

Every time I do this, the money comes out of my account, I get a confirmation email from Blizzard and then my sub doesn’t renew. I have to wait 3 days for the payment to get declined (by blizzard) and then resub.

I ring my bank, they say the funds have been released and it’s on Blizzards end.

I’m starting to think that these measures are in place to deter me from cancelling my subscription after buying it. This has happened for four months running now.

I never have insufficient funds in my account, the money comes out every time but Blizzard rejects the payment.