Their business model is basically let’s sweet talk people into 12 month contracts (because they’re so bad everyone would leave if it wasn’t for contracts) on a plan that’s got way more data than you need and once you’re locked in well good luck - the customer service is awful and the stack is almost as old as legacy banks (zero innovation). Customer service is outsourced to overseas slaves who couldn’t care less (understandable considering their pay and working conditions).
Their plans are designed so you can’t upgrade to a more expensive plan on purpose as a scare tactic, so this can be used in store to scare people into buying a more expensive plan fearing they’d run out of data later on and be stuck with a plan with not enough data for 12 months. If you don’t call this a scam I’m not sure what is.
Finally in store when a customer comes in the salespeople are told to “check their account” to see if they’re out of contract and if so to “upgrade” them to the same plan over again just to lock them in for another 24 months, even though the customer originally came in for a totally unrelated issue. The excuse for this is that the new plan might be like 1£ cheaper but obviously the real reason is to lock them in again.
This link sums it up quite well.
Edit: I have been told the contracts were for 12 months (honestly can’t remember) so for the sake of being fair I’m editing the post.