Most people I know, and many I meet for the first time, assume I answer to Ray. I was always Raymond in my family, and have never identified with Ray at all. Sounds like some other guy, not me. But I suspect people are more comfortable calling me Ray rather than Raymond, so I never correct them. In a way your name is the property of everyone who uses it, so I guess they have rights as well. When people say: "Raymond or Ray?", I say "Please yourself."
A further complication is, I never really liked Raymond either. Happy I was when, at the age of 12, I acquired a pretty cool nickname. A few people in my home town use it to this day.