Wow
a fussy muffler shop with an attitude like that its a wonder they still have any business. Any real shop with a bender and some skill can make the pipe for you...I've had full exhaust systems and parts for my old systems made by a few shops weld or clamp these guys don't care its whatever the customer wants. I've got one guy trained in early Mopar exhaust so he gets the tailpipes correct with the small double bend at the end and he trims the tailpipe off at the correct angle... hes a good guy just didn't understand until I showed him in detail what I required. On repairs... another shop did the tailpipe on my old pickup they used a flex disc on a grinder to clean the rust off the the muffler stub once they cut off the remains of my old tailpipe made the pipe expanded the end & welded it in place no muss no fuss. My suggestion is to locate a different shop if you can , I have always avoided the "big name" shops. As an example , One shop is called Economy muffler and brake , The other is Thruway muffler (A.K.A. throwaway muffler)
These guys are pure motor heads . These places don't look snazzy and sanitary as they actually WORK on cars no excuses ....find a shop like that ....