MCC and MNC info is bulit-in in the firmware. They can't be modified unfortunately.

Firmware is up to date? The extender is using the same SSID as the main router's Wi-Fi or a different one? On the iPad, try to forget the extender's network and reconnect with the password. Check if...

Try to update the latest driver of T2U for Windows 8.1. http://www.tp-link.com/en/download/Archer-T2U_V1.html#Driver

Are you talking about VPN connection or anything else? W8968 supports PPTP, L2TP, IPSec Pass-through. Is it what you need? http://www.tp-link.com/en/faq-558.html

What's the band supported by VOO? Are you sure they are compatible with each other? Supported Band by MA260: GSM Band 850/900/1800/1900 MHz HSPA+ Band 2100 MHz

Can you try it on a different computer? If not, submit a ticket here to report the problem. http://ticket.tp-link.com/index.php?/Tickets/Submit