Wrongly flagged on bureaus

In April the Game app for making payments was not working. After trying to make payment for an entire week I phoned them on the 7th of April to get banking details. I made the payment on the 7th via EFT. They sent me a collection letter on the 10th and flag my credit profile with non payment for April. Needless to say I am trying ever since to get them to remove that flag of non payment with all the bureaus. They are useless. Quick to destroy your good credit record for their lack of competence to allocate payments before they sent out love letter and bad reports to the credit bureaus. Do not ever try to phone them as all they can do is escalating the matter to the next person and f all happens after that. But yes we all know by now customer service and customer satisfaction has a ZERO rating at USELESS *********** GAME STORE SOUTH AFRICA!!!!