loud knocking
 

hi i have a 2016 volvo t5 wagon v60 2.5 engine. i brought in to firestone because he was making a squealing sound when driving and check engine light was on. they diagnosed the problem and said it a pcv and spark plugs. paid a thousand ti get fixed. was perfect for 3 days and now making a loud knocking sound from engine. brought it back to firstsone crank and camshaft throwing a code and a spark plug is bent from piston hitting it. they said it needs a new engine but i think they messed something up. any suggestions!