I agree with NotALawyer. The 2004 edition of the NACHA rules states in the Operating Guidelines portion (Section IV, Subsection F, Part 1 on page OG 183) that "In the event that a consumer claims that he did not authorize the Originator to transmit a TEL entry, the RDFI may transmit a return for the TEL entry to its ACH Operator by the ACH Operator's deposit deadline for the return to be made available to the ODFI no later than the opening of business on the banking day following the sixtieth calendar day following the settlement date of the TEL entry."
So, while you are obligated to honor the RDFI's request that the TEL authorization (which must be kept on file for no less than two years) that is retained by the Originator be sent to the RDFI within ten banking days, this seems to me to be a sideshow to the real issue about accepting a return of the TEL debit from the RDFI. I would maintain that such a return is grossly untimely and you can accept it if you choose but are not obligated within the NACHA framework to do so.