If you would like to talk to someone about your experience at a SONIC® Drive-In, please call this toll-free number, 1-866-OK-SONIC (1-866-657-6642). Operators are available seven days each week from 8:00 a.m. to midnight, EST. This toll-free number is provided exclusively by SONIC Franchisees as owners and operators of SONIC Drive-Ins.
If you are a member of the media and would like to inquire about a story idea, please submit your request to Anita Strohm at email@example.com or (816) 423-6188.
This was all I could find online. Hassle these people.