Bike shop potentially damaged cassette

Took a wheel in to have the cassette removed at a small local bike shop. They did it there and then, but it looked like the guy put an awful lot of force through the chain whip. Left with the lockring loose and the sprockets still on the wheel so that I didn’t lose them. Got home and the fourth sprocket in has dug into the freehub body, and it won’t come off. Went back in and very politely asked if they could explain this. They said it can’t possibly be them, they had done me a favour by doing the job in the first place, that I was whinging and called me a liar. He also said they used the second sprocket so it can’t have been them. I’d love to think my legs were strong enough to do this through cycling alone, but I can’t see how else the damage could have occurred. Do i just suck up the cost as an expensive lesson (~£100) learnt? Or try and pursue it further? Appreciate any thoughts

Chew is fairly normal (in my experience anyway) from general riding & depending on the hub material. Pry it off, fit a new cassette and forget. Try and torque the new one on to ensure it's tight enough - I've read that not having them on tight enough can cause more chew.

This is standard on aluminium freehubs. Switch to stainless steel or sram xd body if you don't want to deal with it.
Remove the cassette, file the freehub body, put new cassette, ride.

That attitude stinks, calling you a liar to your face is not on regardless of what they think. I'd be pissed off enough to pursue, would be pushing for a new cassette at cost price at the very least. Threaten to blast them on social media.

Another voice here saying "yeah cassettes do chew into alu freehub bodies". It's quite annoying.

Some freehubs do now have steel inserts on some of the splines to try stop it happening.

Appreciate any thoughts

Storm in a tea cup. Cassettes do this.

In my experience, these days cassettes last longer than free hub bodies / bearings.

Went back in and very politely asked if they could explain this. They said it can’t possibly be them, they had done me a favour by doing the job in the first place, that I was whinging and called me a liar.

Presumably they felt you were accusing them of causing the damage. That you believe they were responsible probably came across, triggering their snotty response. No winners by kicking off about it on social media or whatever, just get on with it and fit a new cassette.

It's why Shimano persist with steel or titanium only.

Very much what @Howard said

Thanks for all the input. I did go in open and polite, and would have totally just accepted it if they’d said anything like the above. Just didn’t appreciate the attitude. Having read other reviews since, seems sadly common place in that shop. Going to leave it, totally agree nothing gained from bad mouthing online. Cheers

Very much what @Howard said

This.

You can file those bulges if they're stopping you from getting a cassette back on with a flat file, it's a quick job.

Switch to stainless steel or sram xd body

heh, you'll know when you get cassette bite on an XD driver :)

Don't tell me these wear out too. It was one of the reasons I went with eagle instead of new Shimano 12 speed.

Not so much wear out more that the carrier ever so slightly bites in to the alu splines.

This has the effect of it becoming impossible to separate cassette and driver by normal means - because of the way the cassette tries to vertically extract itself through the splines as you attempt to back off the lockring.

Makes sense. Shame that no one seems to be making xd drivers in steel.