I take it you found this problem during the inspection period of your purchase? This is why they have them. I am glad he is working with you. It is a shame anyone would treat a ML likes this. It just boils down to being lazy and not caring for his rifle.

I would just send it back and find another one that you can inspect before you buy. Buying a used ML through the mail is an iffy proposition at best. I have only bought NIB through the mail.

In the future, I would ask a lot of questions to get the seller on record before I commit to a sale.