Legally binding email fees & contract agreement [ location : USA ]

Can I put a footer in an email that is a legally binding agreement if I can prove the email was received by the other party and by responding to it they have accepted the terms ?

For work I frequently contact companies for quotes. Location: il

Over the years corporations get bough out or change marketing teams which results in a stream of new marketing emails, newletter, updates, promos, sales, events etc on topics of useless time wasting spam.

I have already unsubscribed from these previously or have notified the sales rep of my terms concerning spam being sent. My request is usually ignored. I can not even setup a block for the spam emails as they usually use some new email address to send them.

Several companies do this every year now despite my efforts to cease the annoying unnecessary junkmail.

Recently I added a footer to my email that states clearly that I charge an “email fee” ( $1,000.00 ), per email, for any marketing emails that have a “unsubscribe” link in them.

I state that by replying to the email they are agreeing to pay this fee and it is due in 30 days of them sending their spam email.

I also follow can-spam act requirements to be removed from these lists ( documented screenshots of unsubscribe link being clicked or confirmation from rep email address has been removed from marketing ). A year or 6 months later the emails start again.

The footer also states that any emails that are sent in response to an inquiry by us, any emails on orders or assistance in fixing an issue are exempt from this email fee. Basically any email with an unsubscribe link is billed, any other email that is not marketing is excluded from any charges.

Would my email footer for spam charges be an enforceable agreement ?

Also some US states where these companies are located have laws about spam. One company I worked with broke these state spam laws several times. Can I sue them for this or do my states laws, where my company is incorporated, only apply as the receiver of the email ?

These emails were sent by a Colorado company.

Corporations are not interested in following federal law and any complaints I have made over the past 15 years to the FTC has resulted in 0 action.

On a related note am also curious about suing a company for email harassment. Had one company rep get mad and start spamming my inbox with inappropriate links to buy “toys” online minutes after sending a cease contact email and we were going with their competitor. I called them out on it and the spam immediately stopped. They also spammed my phone with text messages that stopped immediately after I told them I knew they were the one doing it. < 5 companies have that exact contact email with my personal phone number combo.

Is there any legal recourse for the harassment or would proving this be impossible in court ?

Thank you for any info on the subject.