Has anyone got GUEST wifi mode working properly on Archer vr500v?

I received this with Kogan broadband order 6 weeks ago, and paid $70 extra for it, thinking it would be highly capable modern router !

For some time I thought it didn't have Guest wifi option but then accidentally found out the option can only be seen in the Admin interface, from a mobile browser !

It allows me turn on Guest wifi , set an SSID, and enter a password, but after hitting Save and seeing a 10 second "reset" of the router, I end up with the Guest SSID but no security (ie an OPEN wifi network!). 

Have tried many different ways including using different phones, different browsers, different length passwords from 8 up to 32 characters, complex passwords and number-only passwords , but nothing changes result.

Kogan support is useless as the first time I rang , the guy didn't know what Guest wifi was.

After I discovered the Guest wifi option on my mobile browser I rang again , and the 2nd guy stepped me through exactly what I had already done , and when I told him I ended up with an OPEN wifi SSID , he just said " well if it doesn't work then it is not a supported feature by Kogan" . I then asked about firmware updates and he said there won't be any!!

As a few others here found out , this model does not appear in the the "Model" dropdown box to start a thread , and on the TP-link website no info is found for this model when searching the entire site!

And yes I know I could pay $50 for a full featured router and set it manually , but just annoyed that Kogan FAQ say they highly recommend their supplied router for "the best experience and support"!!