Unlocking Samsung C170

Question

Hi.
Can you help me. Am trying to unlock my Samsung C170/T Mobile and put in another sim. unlocks ok can use new sim but when l turn off phone and turn it on again it comes up enter password. l enter 8 zeroes it shows wrong card then l enter the unlock code*2767*688 and imei number and it works again.
here is the codes l am using.
Code l *2767*688& imei no.
Code 2 *0141#
Code 3 8 zeroes.
Any help would great...Thanks.
Tina