Hi ​@Moona shahzadi  sorry to hear this, can you please try rebooting your device? Thanks.

Did you pay your bill via the automated system telephone system? 
 

I’m not 100% certain on this but it could take up to 24 hours for the payment to reflect and your phone number to be operational again

It sometimes can ​@L0rdvega  but a reboot often helps too.

If it still isn’t on, please let us know ​@Moona shahzadi