Then you need to contact those companies about this spam emails.

I have contacted every company that is sending me unsolicited mail and messages. It is a 3rd party that they have hired to advertise for them. I have called the 3rd party (in most cases it is TABOOLA). They said that they were hired by the companies and cannot delete me. So, I am being sent back and forth with no resolution. I am certain that many others are encountering the same issue. It is an internet "curse".

Then use your email to block those email sender address. Also this isn't a Firefox issue persay.