Second opinion on Mechatronic unit

[Oxylis]

Hi all,

I posted on another forum and got great advice and support there and as a second opinion I thought I would also ask you if that's ok.

Here is the story:

I have a 1.8T FSI A3 with the 7 speeds DSG. As you may be aware these DSG have been recall for changing the oil to avoid an electronic malfunction in the mechatronic unit.
All good for me the "campaign 34F4" was actioned by Audi last Wednesday.

Saturday (about 15 miles after) the car wouldn't start (ESP fault) which turned out the mechatronic unit needs to be change because of electronic malfunction.

Now I see 3 scenarios here:

1. It's related to the campaign 34F4 and the damage was already done, so changing the oil didn't do anything to prevent the issue.
2. While changing the oil something was done which shouldn't have.
3. The a huge coincidence and I'm going to have to pay the £1700 to replace the unit.

The status currently is Audi sent the mechatronic unit for "expertise" which they told me was standard procedure but my thoughts are they are trying to push for scenario 3 that it is nothing to do which them.

What are you thoughts on this, anyone had similar experience ?