Fabulous Charged Me Despite Cancelling My Free Trial and No Active Subscription

I have been regularly charged for my free trial subscription even though I cancelled it with Fabulous upon learning the app was not for me. Although their website displays no premium subscription active, they are billing me £23.99. I'm lucky in that I didn't lose any money since I was able to delete the card linked to Apple Pay as they were trying to charge me. I see a lot of individuals with the same problem who are being constantly charged due of shockingly poor customer service. This arrangement seems to be meant to guarantee that, even if only once off and at the disadvantage of their consumer base, they at least get some form of remuneration.