Hopper complaint: Bad Customer Service when trying to correct booking

I booked a round trip flight and wanted to add on cancellation for any reason, but mistakenly added on the cancellation if airline delays for 1 hr or cancels. I called Hopped immediately to advise of my mistake, said I do not want the add on I booked refunded (my mistake, I’ll pay for that), just to add on cancellation any time. They advised per terms and conditions they cannot add on after booking. I spoke to a supervisor (Doha) who verbally said she promised they have never done that for a single client ever (which I find hard to believe). This is just bad customer service. I called right away and wanted to pay for the add on, and I was told I had to cancel my reservation, re book, wait for the money to be returned to me since it had been sent to the airline already…. I understand calling in a long time after you book to add it on, but when I called right away I should be able to purchase the add on.