LAST EDITED ON May-17-12 AT 10:53PM (MST)[p]It would be the company that manufactured them. The higher end glass will have a warranty that may cover a seal failure. Scratches, I expect, warrant replacement of the lens. If you have to pay out of pocket for all of the repair work, and the manufacturer will even do it, then you may find its just time to get a new scope for the cost.
What brand and model of scope do you have?