Amazon have been stealing £7.99 from my card every month for nearly two years. It is impossible to contact them for a refund from this sharp practice. I managed once by premium 'phone line, but the call ate up all my credit before it was resolved. How do I make contact by email?
they will call you if you follow the proper procedure
Help (link on bottom of page)
Need more help?
and no, they have not been stealing money from you. That charge is likely for a program like Kindle Unlimited, Amazon Prime, etc that you, or someone registered to your account, signed up for by accepting a free trial and not reading all of the verbiage in the pop ups where they state that it is up to you to cancel the trial after 30 days and that if you do not, they will (they do) presume you want to continue the subscription and charge you monthly. Even clicking the Read for Free or the Free Shipping With Prime could sign you up for one of those programs.
ETA: email is absolutely the worst way to contact Customer Service - use Chat if you're concerned about the phone charges
Amazon doesn't charge for Help so you may have been speaking to scammers. If you gave them any personal information I suggest you change your Amazon password.
To contact Customer Service, click on Help at the top or bottom of any Amazon page. Select "Need More Help" and "Contact Us", sign in and then select "Prime and More". In Section 2, select "Update Account Information", "Other Account Updates" and "Other Account Updates". Then select the Phone option and Amazon will phone you in less than a minute.
It doesn't matter much which options you select as you'll eventually get to the Phone option.
When you speak to them, ask how and when you signed up for Kindle Unlimited. It was, almost certainly, when you or someone with access to your account, clicked the "Read for £0.00" option against a Kindle book.