2008 Gulf Stream Vista Cruiser Tail Light bulb holder

the bulb holder will not stay in the tail light assembly and we are looking for a new one to replace it. I've checked the Gulf Stream web site and see no parts lists ... Auto Parts stores don't carry it. Where do you go to get replacement parts like that ?? One RV place said they'd order it with a $50 minimum order ??? We haven't tried Camping World, would that be a place to check ?

Thanks in Advance ..
Vickie