SITTING WITHOUT A TV FOR 2 MONTHS NOW

My brother bought 2 Sansui TV's 4 months back and one of the TV's didn't wanna switch on 2 months later and we took it back to the shop but they are refusing to take it to the repairs because we don't have paperwork and the person bought the TV is out of the country.i phoned the store numerous times and I gave them details of the owner but they say they cant find it on the system