Easton-Berry Collections

I'm really disappointed with the service from this company, their staff are unprofessional and the managers are useless, I've settled my account in June and I have been calling them every week for my paid up letter and I still don't have the letter, Ive been requesting to speaking to their managers but everytime when I call its either the manager is not available or that the manager will give me a call back, I don't understand why is it so difficult for them to send me my paid up letter