I canceled a mobile phone contract on January 9th with a termination date of 09.02.24. 
On 9.02.24, I received a bill for the period 01.01.24-31.01.24, and I still haven't received any bills for the period from 31.01.24 to the end of the contract (09.02.24). Is it normal to wait for the final invoice for a long time, or does it mean that there is a problem?

Thank you!