This sounds like a form of an installment sales contract. If the buyer is in breach, you should be able to take legal action to cancel the contract and have them evicted. You need to consult with an experienced attorney who can assist you in interpreting the written agreement and enforcing your rights.
David Puryear is an employment attorney licensed in North Carolina with 30 years' experience representing employees in disputes arising at work. He also represents employers in these matters. His general civil litigation experience includes a broad range of business and personal cases tried to jury verdicts. The answers provided here are for general public service information only and are not intended as legal advice in a specific case or the practice of law in any jurisdiction other than North Carolina. You should consult with an experienced employment attorney near you to receive legal advice about your personal situation.
I agree with the Clerk. A "contract for deed" sounds a little strange. Is there any chance it was a lease with a purchase option? If so, then you should be able to have them removed without an issue because all leases with purchase options must be recorded with the Register of Deeds within 5 days of their execution per NC law. It sounds like they never bothered to get whatever you have with them recorded, so essentially they would have a periodic tenancy (that is, month to month de facto lease) with you as their landlord. Whatever the case, this sounds like something you should contact an attorney for as whether or not you prevail will depend upon the details.
You should have this reviewed - most likely the agreement does not meet the requirements of NCGS 47G which covers lease with option to purchase. Those have to be recorded and should have been prepared by a lawyer. If you just pulled a form online then it probably won't accomplish what you intend for it to accomplish. You should have a lawyeri n your area look at this because you may have given the tenants a constructive interest in the property which might make it difficult for you to sell the home or evict them.