Yes unless Nominet UK made the direct change then, the sole and only other people that can make a change is your domain names company (they would be Nominet Members).
However if you have not paid your renewal and been detaged then that's your problem.. it can sometimes happen that a fully paid up customer gets a detag in error, very rare but can happen but that would be an admin mistake.. most domain names companies have rules to say this can happen.
If you want to know what really happened to your name call Nominet UK on 01865 332211, tell customer service that your domain name company said because of your error I got my nameservers changed.. they will then check for you who changed it last, what email address it came form and what time.. or they will say yes sorry our fault.
Last night the Nominet database was offline for 12 hours, that meant every single domain name company in the world could not check .uk Whois.. so if you had been an affiliate of any you would have had no sales for .uk name but what can you do if the main guys database suffers a DoS or Datamine attack.