The firmware can support SSH because TP-LINK added the support of Tether 2.0. Tether 2.0 is an APP used to manage and configure routers; to guarantee the safety of the communication process; they use...

I thought it was the first time for you to install the range extender... So it works but connection is not stable? After firmware upgrade, did you reset the extender to factory defaults and...

What's iOS version of your Mac? You tried the utility here? http://www.tp-link.com/en/download/TD-W8968_V4.html#Utility

Ask some computer technician to test your computer. If the network card is the problem, you may have to buy a new one and install it on your computer.

Why do you keep turning on/off your device 3-4 times? Maybe it is the protection mechanism to avoid damage to the chip caused by frequent electricity power cuts...

I see someone solved a similar problem here with a different model. You may try in the same way to contact support in India....