I have a 2005 vehicle I want to trade in or use for down payment but the mileage is 228000, would they still work with me ?

Probably not... I've been dealing with these guys for a while now for about 4 years. Think about it this way, if you owned M&S would you? 228,000 miles is a LOT of mileage. You would be better off just selling the car by yourself.

Better sell it on your own, and wherever they give you, used like a down payment.

I've no idea. I would try a corporate dealer, Honda, Toyota, etc.