NEED SOME EXPERT ADVICE HERE
Mechanic would have me believe that the bearing in the tensioner went and thus cause of damage. However, I am of the opinion that they did not
fasten the bolt on the unit. Big fight!! Can someone tell me if the bearing failure could cause such a catastrophe

If the idler fell off because they didn't properly attach it, that would look much different.
Should be pretty easy to tell the difference. Ask a third party to inspect it.
My tentionor was replaced also i had a ugly sound which caused me to replace it the bearings would have been screaming for them to explode and do all that... My theory



