Slow very slow service

Very disappointed with the fact that I settled my account. Last week Thursday asked for my paid up letter as for I did an immediate payment. On Friday I asked again and they will let me know. Today I get the response from a lady that my letter as been emailed. When I told her I have not received anything she said delivery times may differ. Like really since when does an email have a delivery time. I finished paying my account quicker than arrange now they taking their time. I want my letter.