It sounds like Pakt Publishing might be bounded by law, and you're experiencing a consequence of Russia's invasion of Ukraine.
> Since Packt is based in London, is this even legal? A quick search shows the following: The Equality Act 2010 makes it (...)
A quick read of Wikipedia's article on the International sanctions during the Russian invasion of Ukraine show that the UK enacted a number of sanctions targeting the banking sector, including a deposit limit for Russian citizens in UK bank accounts.
I think that you might already be aware of that, and if that's the case you're making a very disingenuous and bad-faith case against a publisher, which is rendered obvious by the way you purposely omitted any reference to the root cause of the whole problem: Russia's invasion of Ukraine.