Unfair default listing

I was on errears for 2 months with Unifi and on the 17th and 18th November 2022 i paid up the account and was sent a paid up letter which states that the account was paid in full.the company didn't submit the paid letter to credit bureaus and my name still reflect under default listing as if i still owe them.it is been 2 months and nothing was done.i called them countless times without success.