The actions of Fabletics are unlawful - please feel free to use the below when complaining and demanding cancellation / refunds. Citizens Advice will also take complaints (in the UK) and have referred the matter to Trading Standards and suggested we make a civil claim against this company.
The practice of automatically charging every month for something you don't want is known as INERTIA SELLING and is Illegal under UK Law (Consumer Protection from Unfair Trading Regulations 2008 as amended)
Their website has the "VIP Membership" as a default, not an opt-in. This is unlawful per The Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013 which provide that "no payment is payable in addition to the remuneration agreed for the trader's main obligation unless, before the consumer became bound by the contract, the trader obtained the consumer's express consent", and also confirm "express consent cannot be granted if inferred from not changing a default option"
The website has a 'countdown' of a 1 hour special offer reduction, which is also illegal per Schedule 1 of the Consumer Protection from Unfair Trading Regulations - "Falsely stating that a product will only be available for a very limited time, or that it will only be available on particular terms for a very limited time, in order to elicit an immediate decision and deprive consumers of sufficient opportunity or time to make an informed choice"
There's also another wonderful gem in the Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013 which could potentially be taken to mean if you 'purchase' something with the 'credit' that they've taken it's to be treated as an "unconditional gift to the consumer" and you can keep it - however it's a bit of a grey area and I don't want to have to deal with this company ever again, even if I thought I could use a loophole to get things for free.
Trading standards are now investigating their actions, and have full copies of the website as it was at the time of my purchase. They are unlikely to get away with keeping this practice up. I believe BBC Watchdog have also shown some interest.