Dear Mrs. Smith,
I am writing to say about problems with the English course which you offered me. I have doubts concerning this course because you told me that I would get a certificate ending the course, but it ended one month ago and I did not get anything. Moreover, I have to pay for the course more than it was written in the leaflet. I have attempted to contact with you for two weeks by phone, but it is completely impossible.
The certificate is really important since it will confirm my qualifications in my new job and my earnings do not allow me for such expensive course.
I hope I will get suitable documents and that I could pay amount of money which was registered in the leaflet, not more.
Could you tell me when we can meet and try to solve these problems?
I look forward to receiving your reply.
Yours sincerely,
xyz