Walk Behind Lawn Mowers

I purchased a 7021 rc and the drive cable broke I order another one and it has a 1/2 that adjust the length of the cable where it attaches to the two drive handles. the one that broke is around a1/4 with a rectangular nut that holds it in place. I have talked with HSQ escalation REF #93462249 and they are no help at all. They say they will call me back and never do. Please someone help this is a expensive mower that is not working. If I have to buy the right part then that is what I need to do. because my handle must be from another model.