The answer to complaint or general denial form must include the specific statute(s) of limitation that you believe apply to the underlying claims in the complaint. Cite in the answer to complaint, as an affirmative defense: Title 10, Delaware Code, Section 8106.
What's your point regarding the two year oral limitations period? Are you suggesting that they violated their terms and that you wish to counter sue (known as a cross complaint) them?
Generally speaking, preparing a decent response to the lawsuit does not mean that you have the legal skills to present this defense to the court at trial or if the Plaintiff files a motion for summary judgment. My blog posting, linked below, explains concerns with people who try to play lawyer, by DIY lawsuit defense: it often results in a money judgment against them. At least consult with an attorney who primarily handles debt collection lawsuits to see if it makes sense for you to hire such attorney. Check their ratings on Avvo.
Robert Stempler (please see DISCLAIMER below)
NOTICE: The above statements are provided for general information purposes only and are not intended as legal advice or advice of any sort for a specific case or legal matter. If you do not have a signed attorney-client fee agreement with the Consumer Law Office of Robert Stempler, APC ("the Firm"), then until such written fee agreement is provided and signed by both a prospective client and attorney for a particular case, neither Mr. Stempler nor the Firm will represent you nor will they be your attorney in any matter and you remain responsible for retaining your own attorney and for compliance with any and all deadlines and for any statutes of limitations that may pertain to potential claims. Comments made on a public forum, such as Avvo.com, to not have any confidentiality because others may read them. If you desire a private consultation with Mr. Stempler that is confidential, please go to www.StopCollectionLawsuits.com and submit a free eCase Review. The result portrayed for a client was dependent on the facts of that case. Results will differ if based on different facts. The Firm and Mr. Stempler are a debt relief agency. The Firm and Mr. Stempler help people file for bankruptcy relief under the Bankruptcy Code.
Statute of limitation applies when sufficient time has passed according to the state you live in and the type of debt. The challenging part is that there are a long list of events that can trigger an extension of the statute, such as paying or modifying the debt during the running of the statute.