Possibly something to do with American websites not being able to hide details from whois database so some folk try to get around this with UK domains that can. Maybe, and it's just a guess, but there may be something ICANN don't like?
All this is pure conjecture of course and is most likely competely wrong. But it's my new pet conspiracy theory!! Along with the Moon really being made of cheese, and those 'craters'? nothing of the sort, have you not noticed how much cheese there now is after men landed on the Moon?
Joking asside, you would be best phoning up support on this one.