Problems with phone and no help from Customer Support

I received the Galaxy S as a replacement from the HTC Sensation and in the phone is a nightmare so far is my 4th phone and they just basically want to upgrade another line to get a phone and I refused so basically the Customer Support told me we send you the same phone and 35.00 discount. I felt like a slap in the face... I am wrinting to The T Mobile Complaint costumer realtions team at P.O Box 37380 Albuquerque NM 87176-7380. I have been a customer for over 9 years and I have been  paying for their insurance for 3 lines and  I think thats would at least can do an exange for better phone.