decat fitting

so before my mot i asked the garage to take off my 3inch decat as it would obv fail.  and i didnt wanna spend the time on my back swapping over again!

anyway today i got around to refitting the decat only to discover the garage had obviously snapped a thread because there was a massive bolt head in its place, no they did not tell me this at the time.   this bolt is also been done up by the fecking hulk!

i am concerned it has been brutally put in there maybe even cross threaded...... 

this was back in augustish do i go back to the garage have a moan? i feel i should as i will have to get the hulk to undo the bolt as i cant get it off on axel stands. 

it should be known i swapped the original pipe for a deact myself and never snapped a thread,.