A few years back we sorted out a Cessna 172RG after a UK maintenance company left a role of masking tape in a fuel tank. The whole fuel system was contaminated with glue.
We sent all the components back to the maintenance organisation so they could control
their costs and we then sent them a bill for our time. This they refused to pay!!!!!!
I pointed out that we were trying to rectify this on a friendly basis but I was more than happy to make a full report to the CAA .
Cheque came in the next post.