YourTeacher.com Customer Service Issues

Upon reviewing our Discover card statement, my husband found a recurring charge of $49.99 for a service called teacher.com. We traced this back to April 29, [redacted], and discovered it links to mathHelp.com, possibly from when I signed up our eldest daughter for Accuplacer help before she started college. However, we ceased using the service in July or August [redacted] after her exams. We were billed around $[redacted]-$[redacted] in total for 13-14 months. I am unsure why the charges continue as I did not subscribe to any ongoing service. Unfortunately, I couldn't find a phone number for assistance. We aim to cancel immediately and seek a refund for the unused months. We are eager for a prompt response and resolution. Thank you.