Nokia / Model N70 — malfunctioning of product

I have purchased N-70 music edition set in sep - 07. Since last two months my set is behaving abnormally. During the call (both incoming & outgoing)

1. Various menus like music player, gallery, fm radio, loudspeaker etc. get activated automatically and call gets disconnected.
2. During this process many beeps could be heard and digits like 0, 4, 9 etc also appear on the screen and call gets disconnected.
3. Sometimes the callers phone number appears in the received call list, whereas I have never attended the call (because no ring, vibration etc.) and every time my colleagues keep on telling that I didn’t attended the phone.

I visited Nokia Care, Indore where after keeping the mobile set for a day and re-installing software etc, I was told that there is some hardware issue and it needs to be sent to Bhopal. I contacted Nokia Care, Bhopal and handed over my set to them for two days. I was told that the problem is rectified. But still the problem persists and I am in trouble

Since the set is in warranty and there is some manufacturing defect, I request your kind self to kindly look into the matter and give a replacement of the set to me at the earliest