graco swing not working anymore

I got it at my baby shower my son is about to be 2 months he's barely 10 lbs so I know it's not his weight the swing has a plug in option and a battery option and It doesn't swing with the batteries or the plug in  and I'm going crazy he loves his swing and it won't work I don't have the receipt so I can't return it I'm wondering if there's something I can do to fix it