Need Help FC2250 issues and Tech did repairs wrong and wont back it

A few months ago our FC2250 went down. We had Tubelite down and they replaced some parts - no go. Graphtec said try the next parts.... none worked. each time had to wait for techs and parts. At the end Graphtec said - Oh well you needed to put all those parts in at once - putting them in piecemeal can short them out. Tech company tells me - the parts we had promised we would credit - we wont credit anymore because maybe there is an electrical issue with them.
Question - How do I fix - we need to put all the parts in together - means we need to buy all new parts.
Graphtec tells Tubelite they installed wrong - Tubelite tells me - too bad you have to pay for the parts because its electrical issue. Shouldn't they be covering it? IF its electrical - the parts were only ruined by their techs incorrect install? They should fight it out with Graphtec after the fact. Am I wrong?
I am stuck and I need this cutter back up. At this point it seems my relationship with Tubelite is down the drain, which is a shame.