Pathetic service bmw

Bought my vehicle In Feb 2018, went into some water due to heavy rainfall on the 30th of December 2018, booked my car in for service as there was nothing wrong but wanted to clean the grass and sand I found on the grill. Service department told me it's an Insurance claim car needs to go to repair shop took it there, having endless drama with the insurance Company when I bought the vehicle I was told bmw has its own insurance so I took it thinking that in the event of any issues it will be dealt with swiftly as its all under one umbrella only to now be told since there is a claim its not there company its an entity on its own but if you call this company they greet you with bmw finance, at the end of every email has bmw finance, so they found water in the air box repair centre says engine has to replaced as they do not repair and they can not tell the extent of damage as they cant open the engine. Ium which is the insurance refuse to pay, we have called bmw even went there they say it's not their issue it's insurance but the insurance says bmw. It's Almost a month I don't have my car I keep calling the insurance or bmw nobody calls me back, when we buy the vehicle we are treated like royalty after the deal is done your dirt. Never expected this behavior from such a massive company. Don't ever purchase a bmw you will have endless issues and be treated with no empathy and disrespect.