Someone "who has been driving cars for a while" doesn't mean they know them mechanically, which shows since the cost to repair your vehicle is nearly what it's worth
.
The next time, do a search on PPI to learn how to get one done, which is money well spent to know what you're getting prior to purchasing.
Maybe join the bmwcca ny chapter where you can find where the local people in your area bring their BMWs for trusted repairs.