Ongoing RingCentral charges for unsolicited faxes and phone calls on my supposedly $10 yearly fax only account..

Years ago I signed up for a Ring Central limited fax-only account for $10/year. During the entire period of my subscription I have used the fax service only a handful of times. Last year, charges appeared on my account for (unanswered) phone calls. So far the charges have added up to almost $40. Last Fall, a service rep promised to refund one of the charges but the credit never made it to my credit card. I've since found a setting to block all calls but not at all sure that this will stop the additional charges. Needless to say I am frustrated, If I can't get this resolved soon I will have to cancel my account and re-do my business cards without the fax number. Probably should have done this after the first overcharge.