Any good commercial truck shop should be able to fix this quickly , provided the brakes aren’t coated ( a major fire danger don’t drive it if they are ) . Even then it should be a normal repair as these are standard truck parts. The problem is finding a component repair shop.they should be able to tear it down and fix it knowing the issues you’ve told us. They need to look further than a simple seal replacement . You’ve had a bad run of shops is my guess and these hub seal repairs are normally simple and sometimes given to the “new “ guy maybe that’s what’s going on .. good shop bad mechanic. I’d call the shop it was done at and raise H ..
