Like Bon Ami or something similar?

I would not mess around with at-home "etch removing abrasive". You should hire a marble refinisher. Your counter will look like new. It is very important to get a very good quality contractor for the marble refinishing. I.e., don't use a contractor that does e.g. rug cleaning, painting, duct cleaning, and also marble refinishing. Hire one that just does stone refinishing.

Having said that, your counter will get etches from normal everyday use because there are always going to be spills. That is just living with marble. But what you described sounds like the entire counter is ruined, so for that I suggest refinishing.

Have it professionally refinished please. You may want to schedule a MORE Anti Etch or a www.stoneguardusa.com treatment immediately afterward.

Thanks so much, all. I have requested a quote from a firm called Marble Doctor, so I'm hopeful they will be able to help.

Provide your own marble cleaning product and tell your cleaning people to only use that product in the kitchen. I use a sharpie to write on cleaning product containers, to show what surface it is supposed to be used on (wood floor, tile, kitchen counter, shower, etc). For a couple of weeks double check that they are using the right product, specially if you have a couple of crews that rotate.