How much was the unpaid bill?

100 eur

That is the limit so a block would be justified. However, you should have received a letter notifiying you this would happen. If you did not, maybe check in your customer account that the contract and billing address are correct. Also check your SPAM folder for any mails you might have missed.

If you can pay now with a quick transfer your SIM should be reactivated within 48 hours. Make sure you enter only the customer number as the payment reference.

Hello @Simbu1996 ,

welcome back to the o2 Community .

We've send out a letter on the 30th of July and then a bit later on the 9th of August an email, in which you were informed about the impending barring of your contracts. Please make sure that your contract information is always uptodate, so that you can receive important information. If you can’t make a complete payment all at once, then please contact our inhouse dunning about your potential options and if there are any questions you have before that, feel free to ask away.

Kind regards, Sven