You'll need to post a bit more information and context than that if you want assistance from the Community Forum.
Is this the same issue that you posted about last month?
What happens when you try to buy a monthly membership plan?
Any error messages?
When were you last able to successfully buy a monthly membership plan?
Is your payment card still valid, not frozen via your online banking, and there are sufficient funds in the account if it's a debit card?
If you need to contact 48 support about this then see the links in my signature below.
