Poor services ever

On the 26 of May, we paid our monthly installment electronically on the account number they sent us when the lock-down started. They claiming that they never received any payment however, the payment done on the 4th of May(For April) they can see it. These two payment were done on the very same account numbers that were given to us. Now, we getting all stupid phone calls that the account is in arrears after they gave us a Whatsapp number to send our proof of payment of which we did and later they claiming that number belongs to Identity, then sent us a different one but we never heard anything after that. Different people calling with the same nonsense is irritating as if we owe you. Can this be resolved ASAP as I can not tolerate it anymore.