QC on Arkham Knight Batman’s bicep

Does anyone have any suggestions to fix Arkham knight Batman's bicep? His left bicep is very loose and on my previous copy, fell off indefinitely. I tried to superglue that copies bicep hold to give the peg more to hold on to (to tighten the joint) and if anything, it worked worse and the bicep wouldn't pop on no matter what. I'm not sure if glue vs kikis will have a difference, but if anyone has had the same issue of it falling off, any advice? Thank you.