I can't pay for iCloud

I use PayPal to pay for ICloud but since like some months ago I always get the notification that Apple wasn't able to get the money. I checked my card information on Pay Pal and my bank account and I got enough money to pay for everything every month but every month I get notified that the transaction couldn't be fulfilled. I tried to remove the payment method and add it again but it says that I have another purchase which I don't have, don't have any subscriptions whatsoever seeing that now they down graded my icloud for not being fulfil the transaction. What is happening and what should I do?