Warranty policies for mechanics in Calgary

Apologies if this is irrelevant, looking for general advices from people who had more experience with.

We got our 2020 VW model SUV assessed and fixed for frequent engine oil leak / engine light issues, at one of most popular mechanic shop for Volkswagen in Calgary.

First they said the oil plug was broken, so we got a new replacement in. Same issues returned a month later. Next visit they said the PRV was damaged, so we got it replaced with new. This was in July and the same issue has returned again. Low engine oil light, and random engine light coming on/off (probably just ~2000 km of millage).

When we followed their guide two times, spent ~$2k, and if the same issue returns, am I in the right position to expect some sort of warranty/coverage from the work they performed? Or am I simply expecting a bit too much.

To be fair, the shop has lots of great reviews and the guys there seem great. I'm frustrated that all the time and money didn't fix the issue, but am unsure how to navigate from here.

Thanks in advance.