...achieve better results than simply posting bad reviews on Trustpilot
For the majority of those users who have been consistently and extensively ignored by Bloviation, posting a public review often results in an almost immediate response. That was my own personal experience and has been the documented experience of many others.
However, this does not preclude an unhappy customer from effecting a charge-back and for the very reasons you cited, I would strongly recommend this course of action as well as making a report to the Trading Standards Authority.
Paul..