RING CENTRAL REAPEATEDLY CHARGED MY CARD AS MUCH AS 4 TIMES PER MONTH OVER LAST 8 MONTH EVEN THOUGH THE ACCOUNT WAS CLOSED 8 MONTHS AGO Internet

I signed up for a TRIAL from Ring Central and required to give credit card for that.  I cancelled 1 day late.  Ok, so I owe then 1 month at most.  I cancelled the account.  They have billed my credit card as many as 4 times a month for the last 6 months.  I have contacted them repeatedly.  Told they would credit.  Told they would cancel the account.  Then the next month, 2-4 charges again.  I have contacted my credit card company.  They remove the charges, then put them back on.  Then this repeats.  I have even had my credit card company change my credit card number.  It is STILL HAPPENING.  I am at my wits end here.  My credit card it CARNIVAL MILES CARD.  I have used them 18 years, but I will be dropping them today if they cannot permanently stop Ring Central from doing this and causing me an hour of trouble and anger every month.