If you want the MBG you need to use it

If you do not use it, you are not covered by it

As said, you choose to buy from a seller with shockingly bad feedback, and then allowed them to play games with you by leaving it to late to open and follow through with the dispute that would have gotten your money back

No need to be tolerant, send emails etc etc

You had the opportunity and power to be covered but did not use it