How often would you need to replace a computer in a car? And what could possibly cause it needing to be glfully replaced?

My sister has been messed around BIG time bus mechanic. She needed ylthe clutch/gear box looked at. Just so they knew what the problem was. $330. Fair enough, big job. Didn't tell her that before he looked.

Told her he was pretty sure problem was in the gear box, rather than the clutch. Asks if its just the pin, should they just put it in. $380. (she thought thiswas total price, not seprate to looking costs).

AFTER telling her he didn't think it was the clutch REPLACED the clutch, then told them it didn't need it... Wtf?

Then some $900 price. They go to pick it up. Car won't start, no power to anything at all. That was Wednesday last week. They closed Thursday & Friday.

Monday morning sister & bilturn up to find out what's happening. 'they're just replacing the computer'. Cue sisters 'what??'. 'we were closed Thursday & Friday how were we sposed to notify you?' im sorry, but that's possibly the stupidest thing I've ever heard... Wait til you're open again might help yeah?

So how do we know it needs replacing & why now?

They also charged her for a rear engine oil seal... Its a front wheel drive? Engine is sideways? Dad says there is no rear engine oil seal? But I assume there's something...

I dunno. It all seems dodgy. Dad called & they're putting the computer in for free, only charging for it & no labour. No phone calls to let sister or bil know anything before work was carried out. Clutch put in that didn't need to be. Refusing to tell sister anything about the car because bil dropped it off, so was in his name? Its her car? I don't get this at all. its not confidential information??? Lol.

So i don't know. If they were closed when did they find out it was the computer & when did they order in the new one?

Its a mess, but im sure this isn't the way any of it should've gone?