Can you be At Fault if you stopped over the white line at intersection and got rear ended?

No, don't think you would be held the majority at fault, and doubt would be any liability assessed to you. The vehicle behind you has a duty to not be driving too fast to ensure he can stop short of any obstruction in the road. If you could give me more details surrounding the facts of loss I could be of greater assistance, if the insurance company has or does deny your claim, please let me know the exact reason for their denial and I'm sure I can point you in the right direction.