Hello. I am really sorry about this trouble with your BRCK.
The current BRCK supports networks only up to 3G. We hope to have 4G functionality in the next BRCK. Since 4G SIMs are backward-compatible, your SIM should still connect with the BRCK.
Can you use the SIM on a phone/ tablet or modem to get online?
When you connect to your BRCK, go to the local dashboard and click on Configure on the SIM tab.
Enter the information below anc click on Save.
username: leave blank
password: leave blank
Please let me know how this works out.