I understand this from someone who has not been in contact with someone during last years, I have and I was very surprised (not that Mike doesn't reply promptly or even reply at all, this I agree happens) that he would use such methods as torch (I would use oven to 50 degrees in case heat would be necessary as splitting up old cemented elements).
So as I was not there either when Mike or OP were manipulating the camera or lens elements I can't assure that Mike used torch, he (and others) has the benefit of the doubt.
And I was only saying that the idea of torch is silly, given the impossibility of controlling the flame and heat coming out of it (for the discussed task), and in such a vicinity of other materials that could be destroyed in the process. There is no 50 degrees from a torch, use hair dryer for that and much higher actually. There are electric heat guns far safer overall that bring the heat much beyond hair dryer too.
Besides, if lens was shipped clean and came back not that anymore, then the hack was done to it. To me the whole story of remaining silent for so long is good enough to place judgment. If you don't know how to handle something you state so, return the item back, apologize for making up false hopes, and at least be a man keep it honest. So no, as far "contractor" goes, I think this went way beyond benefit of a doubt.