Telstra Max 2 Modem

I am having problems with the modem connecting to the internet.
I changed plans in November last year and received the new modem.
It dropped out and could not get it to recover by powering down. Eventually I called the help desk and was asked to push the reset button. This seemed to work for a time. It seemed to only work for a few days at a time. I then went to a Telstra store and complained. I received a new modem very promptly(good service).
 
However the new modem after a few days is doing the same thing. Is there a known problem with these modems or is there a new firmware upgrade available that will fix this problem. The previous modem I had had no issues.