how to get refund for service

I've got an almost two year old Macbook Pro with problems the whole time. Keeps auto-erasing and auto-loading website while I'm typing on the keyboard. December, the screen quit working and I sent it in for

repair and enclosed a letter explaining the keyboard/ autoloading problem. $800 late I got the Mac back with a new screen and letter saying the machine performs up to the standards Apple set for the device.

Within a week or so, the problems started again so I started checking the web for answers, assuming the computer had been checked and noting wrong.

Finally, in june contacted support again, no result so I traded the machine to apple for a new Air. Today I found out the trade-in value was reduced from $625 to $0 because of faulty keyboard. Very upset.... So, I tried to request $800 for new screen returned. The machine was suppose to be operating properly. I was told because I did not call service about continuing problems within 45 days, I'm out the money?? This after they told me it was working properly in December?? Turns out, they don't read enclosed letters I sent with the computer to describe problem, just opened replaced screen and returned. So, It's my problem???

Anyone know of a complaint/customer advocacy contact at Apple???