2004 Toyota Matrix Flywheel

Hi. In February of this year, I got the engine in my Matrix replaced because I totaled the existing one by having a cracked radiator from an impact. There was slight damage to my front end from the impact, but minimal. The damage was due to an overheated engine from driving it afterwards.

In February of this year, I got the engine replaced with a used engine, with 70,000 miles on it by a mechanic in San Diego. About two weeks ago, my car started making engine noise. I had it examined by someone in Oakland because that is where I am presently located, and it turns out the flywheel is completely cracked.

My question is, is it possible that the damage to the flywheel was done during the crash? Then, is it possible that this was then overlooked by the people who replaced my engine? Could they have used my existing flywheel on the replacement engine with the part being compromised?

Or, is it possible that the flywheel has just warn out in the time that they serviced it in february, to now? Less than 7 months?

Any light you could shed on this would be so helpful because I can't just take it to the mechanic that fixed it in San Diego, but I feel like they might be responsible for the damage.

Thank you so much for you advice.