No Service - stopping my debit order

Good day

When you are not ready to upgrade yet they call my and my kids at least 15 times a day , now that I am requesting to cancel one contract and want to do upgrades on the rest , nobody phones back or responds to my numerious emails to retention , they say they called back and could not reach me!!, they called once and when I answered they dropped the call

When you call the call centre you can hear people talking , but no one answers , till they realize there is a call waiting and then they just disconnect , I work in a corporate call centre for a leading company and that would had me fired on the spot