POOR SERVICE

I had an account with Homechoice and the account was handed over to MBD for collection, I have settled account and I have been requesting a paid up letter from MBD since the account is settled but to date I am still waiting, another thing is, I overpaid the account and I have been requesting for my refund and I have been taken from pillar to post, the account was settled in May 2020 and it looks like this company is not willing to provide me with a paid up letter and also not willing to refund me....I AM SO DISAPPOINTED WITH THEIR EXTREMELY POOR SERVICE!!!!!!!!