cottman transmission told me my transmission needs rebuilt - when that wasn't my trouble at all lancaster, Pennsylvania

 i took my truck to cottman trans because it had a bump when i go to pull off, -     day 1 was told not my tranny day 2 was told yes my tranny needs a rebuild, -     now $2200 later i still have a bump when i start to pull off, -     so that tells me it wasn't my tranny in the first place, -     i called customer service and was told there is nothing they can do,      or i could try and take it back to them,  -    problem is i dont trust them now,  -    im afraid they will make something else go bad costing me more money,    i truly believe no matter what your problem is it will always be your transmission according to them.