Customer service: signed up for PRO, but"COURSES Musescore" was added to bill contrary to my intention

I signed up for PRO membership today via the special offer on the website. While checking out, there was a confusing window that seemed to complete the purchase, but was in reality a sign up for an additional service "COURSES Musecore" that I do not want. Now I am finding the chatbot and support email are not responsive. I did this just today. My question: how do I get out of the "COURSES Musecore" charge and get a refund? Thanks for any help!!