If they remove it there isn't much you can do besides sue them for the cost of a replacement.

Your best course if action is probably to send them a certified letter specifically stating that you do not consent to your fence being removed and you will expect them to pay for any damages/replacement. Include a copy of the survey showing the fence is on your property.

Also if you have any other contact info for them - text, email, etc. then send them the same info there. You want to make sure you are explicitly telling them you don't consent to the fence removal.