I have canceled and paid the reminder of a contract (3 months) in 11\5\2020, and received the cancelation confirmation 

few days ago i received an email from O2 demanding a payment of 62.87 euros 14 are for an additional tariff that i forgot but willing to pay for. anyway the rest of the amonut could be explained?

Kundennummer:- **********

phonenumber of the contract:- +49 (0)176 **** 806

thank you for your help

Edit o2_Alina: personal data anonymized