Aside from the coincidence of the tranny failing after flush etc. This is what would concern me: "I have the Volvo towed to Volvo, where they find black ATF with metal shavings". I may stand corrected but surely the fluid could not be black after just 13 miles and two days after the flush????. Firstly, unfortunately you have a transmission problem secondly I'd suspect the flush you were charged for was not done. I'd get the fluid examined and if it's old ATF, hit the dealer for the tranny repair or at the very least a refund for work charged for and BTW check the other workmanship as well.

It happens;a family member was charged $600 for a service by a dealer and an independent mechanic inspected it and could prove that a spanner was never taken to the car-settled out of court.

Good luck.