The plaintiff's attorney shall sign the notice, and said attorney's signature constitutes a certification by him or her that, to the best of his or her knowledge, information, and belief, the statement and supporting facts are true. If a party shows that, when he or she was served with notice under this paragraph, he or she was unable through the exercise of diligence to obtain counsel to represent him or her at the taking of the deposition, the deposition may not be used against such party.
OCGA § 9-11-30