What difficulty?
What happens?
Any error messages?
What exactly do you mean by "my Data Plan"?
There's no mobile data only plan on 48.
Do you mean a monthly membership plan?
When were you last able to buy one?
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.
