No Statement, no proof of paying the creditor and no answers

The service is NON EXISTENT!!!! I paid up the account but Direct Axis is claiming they never received a payment on the account, so where did all the money go especially since I have a paid up letter from Sigma dated April 2019. Mailing and phoning numerous times to get a statement and proof that the money was paid to Direct Axis has been a pointless exercise. Your consultants don't phone back when they suggested to do so, speaking to someone else who just says they will send a mail to the consultant, or this has been escalated, or it has been mailed but the mail has never been received. Where did the money go that I paid you every month?