I am not a lawyer, but my understanding of my liability to my customers in the UK is this: I am bound by the contract of sale for 6 years to provide a physical thing that is 'fit for purpose' or to take 'reasonable skill and care' to carry out a service. Unless it was advertised before you bought it that the game wouldn't work without a connection to a server and that this connection would only be guaranteed to operate for a certain time then you might have an argument. Search Citizens Advice Bureau in the UK and browse their consumer rights section to see what you could do and where to get some actual legal advice.

No. Their terms are highly unlikely to have promised to run said servers forever. If they never got the servers running, you'd have a case for a refund.