Don Brent

Hello all,i am a new member and have a problem that i could use help with.I have a 86 wagon 4wd that i had someone put a new timing belt on [old one had teeth missing and it quit running 50 miles from home,it just slowed down and stopped] That was in Sept.,now the first of Dec. it quit again,yep timing belt.Well i tore into it and found the drivers side belt melted and in pieces.Now this might seem silly but the tensioner on drivers side is suppose to turn with the belt right,well mine is locked up and will not spin.I guess this is what caused the belt to break it heated up the belt.My question is,,,is both tension pullies suppost to spin and how is the drivers side belt routed? Should this have been spoted by person who put new belts on,,by the way,paid $150.00 to have new one put on. Thanks to all who respond!!