Cant unlock my galaxy exhibit from t-mobile want to use att simcard

Hi Can you assist in helping me unlock my Samsung Galaxy exhibit phone please

What Unlocking method you have used to unlock it?
If you used unlock code to unlock your SAMSUNG EXHIBIT 4G model Phone,
how many tries you have left.Because for samsung only 5 unlocking tries are there.If you miss this the phone get hard locked..So i would suggest the site
Simpleunlocking.com/samsung-exhibit-4g/rs16wp9/ here you can get the unlock code at reasonable cost and unlock it from network lock easily and use AT&T sim card in it.

Ur defalt phones codes is 12345 or 00000 u can use it
Default 4 Digit user code: 1234 or 0000
Default 6 Digit Security code: 123456 or 000000

Type *#06# at the mobile screen to know IMEI no of your mobile.
send the IMEI no to me and i will reply you with unlocking code.
IF Problem not Solved So
Please New Software install in the Phone Problem will Solved

If For puk & pin cod problem So Please
Very Best Solution:You Go To Service & Sim Office and Get The Puk code And Pin code From Office oprator
Enter The Puk code and Yes
Enter The pin code and Yes
So Puk code Open and Problem will Quickly Solved