I had this weird sudden realization... for modern day apps and online service providers, with applications such as iFlix, Grab, etc., the best way you can hurt them for bad customer service is not just through not renewing your subscription or paying for their service, but by having your account deleted.
The industry isn't really looking into just the financials any more, but metrics such as activations, engagement, and reach. If you're in their system, you're still counted as a number, albeit an inactive subscriber.
So, instead of just complaining on social media about a bad service that ticked you off and saying you're no longer going to pay them money, do the extra step and have your account deleted and removed.