Calverts express auto care They messed it up St.louis Missouri

 Couple of weeks ago I took my Cadillac to this company I have a 2008 DTS it needed a catalytic converter for what they said I actually got several reports saying the same thing so I knew it was the catalytic converter they agreed to fix it. They tried to put a universal catalytic converter on it but I didn't work it wouldn't seal properly and it kept popping the engine codes so I was advised by them to go to the dealer to pick up a catalytic converter and put it on for free. They attempted to put it on but stated it wouldn't fit this was an original OEM Calendar converter from Cadillac but it wouldn't fit on a Cadillac DTS? They then advise me they would try their best to put it on I advise them to hold off and let me get an opinion from Cadillac dealer the deal advised me to come back bring original catalytic converter back and they would try to fit it and find one that actually fit when I did saw that got the proper catalytic converter and I took it back to Calvert. Calvert put it back on and advised that fit however a check engine light never went off Calvert's express explain that it may be several different things and blamed the catalytic converter from Cadillac. When I asked them to fix it they refused they stated they didn't want to work on the Cadillac any longer because they thought it was out of their expertise. I contacted the general manager or district manager is he called himself and he showed no caring whatsoever about the problem. This problem however has never been resolved after spending $1,200 on it was Calvert's.