Transmission Rebuild

Had my transmission rebuilt here. (All new parts they said) Went bad within a 2 month period. I took it back to have them repair what they had done. I therefore should not pay for something that was never properly done in the first place. I was told I needed to pay another $1000. When the initial new transmission was $2500. They "fixed" the problem for me or so I thought. Another 2 months goes by and it goes bad again. I now have taken it elsewhere and they said that the transmission that was put in with all new parts by Bonantis is garbage and has to be completely rebuilt again costing me another $1800. I will never recommend them to anyone and will try to spread the word about how they treated me. When I told my most recent mechanic about this he laughed because it's not the first time this has happened.