sim card is not showing

hello!

i bought iPhone5 by contract "pay monthly" in 2014 in UK, it was working in Russia as well but now shows that 'no sim card'

I checked that some phones were bought by contract will not work in different countries if you didn't finish you contract payment but I paid all price and used in different countries.

also I don't know how to start chat with apple support here, now i see only calls and offer to go to apple centre, i can only chat or write to apple email if they have, but I did not found,

PLS help me!