For all of those on this forum. We can agree the surface pro 4 battery problem (maybe even the device itself) and the way Microsoft is dealing with it suck.
After fighting them for several months I realised I was getting nowhere and started looking for (self) repair options. I landed on a repair shop in Amsterdam that replaces the battery for 100 EUR. I just had it done last week, and first impressions are excellent. I got the unit back within a couple of days and it seems to work fine. Will post again after a few months of testing it out, but wanted to share it for those that happen to live in the Netherlands or plan to visit someday.
The shop is PrimeRepair on Leidsestraat 42. Mobielreparatie Amsterdam - PrimeRepair
It's not ideal. But for 100 EUR i figured it was better than throwing it out or living with a firehazard in the house.
Hope this helps.