My phone is unlocked. But I can't top up with 48 why
How are you trying to topup?
Any errors etc.?
What does your online account say about your membership status, expiry date and allowance balances?
Hope this helps.
How are you trying to top up?
i.e top up voucher, credit/debit card
Is the top up present on your account page? ]
Remember with 48 topping up isn't enough, you need to convert that credit into membership