Airtime cancellation headache

I have been trying for almost a year to cancel my airtime subscription with RMCS. I have called their centre numerous times and given several reference numbers (EDCP-170 ********** 672, EDCP-170 ********** 828 and EDCP-171 ********** 475. These are only 3 of the many that I could find) . They say they will call me back to complete the cancellation but they never do. Whenever i follow up they say they called and I never pick up even though i have NEVER received a missed call notification from them. I am sick and tired of this nonsense. My cellphone number is **********