Ni, you do not have to give them permission to use your private road.
You should seek the advice of a local real estate attorney to seek an injunction.
If this answer was helpful, please mark it as helpful or as a best answer. This answer is for general education purposes only. It neither creates an attorney-client relationship nor provides legal guidance or advice. The answer is based on the limited information provided and the answer might be different had additional information been provided. You should consult an attorney.
Based on the limited amount of information, i would say no. Verbal permission gives the company a "license" as a matter of law and that does not give the company an easement. Additionally, there are many other issues that arise under the fact pattern you raise. My firm has handled many cases related to the issues you address. I agree that you may have to go to court if you cannot reach a solution.