Unlock code (by 2 users)

I bought a pantech c810 & want to unlock to use on T-Mobile.

I bought an unlock code but does not appear to be correct

The unlock code box only allows 8 characters & the code received has many many more characters.

Question is: how many characters should the code be? & is there any special way to input other than install the T-Mobile Sim card, powerup & enter code & pin twice.