switching tablet to qlink (T-mobile)

im trying to switch my unlocked android tablet 9020A to qlink wireless and the network selection options search and finds both the "t mobile" and "313 100" networks that qlink wireless's website states i need to choose from to activate and use my new (bring your own device) device with their service but both of them have "(Forbidden)" written immediately after the carriers name and wont allow me to connect to them (hence the : forbidden statement) but i have just recently unlocked the device and did my tasks needed to be done on the qlink side of this problem, and now ive resorted to factory resetting the device, disabling any and all att apps i could find and cleared their cache andd app data, yet still i cannot get the tablet to allow me to connect and idk why because i just got it unlocked so naturally i thought , i should be able to connect to any carrier given i have the proper/respective and valid/legitimate sim in the tablet....  but this is proving to be nowhere near the case in reality..............): help please!