ReadyNAS NV+ and 3TB HDD

I have ReadyNas NV+. First I bought Seagate Baracuda 4TB disc and end up with only 1.6TB size for Volume C. Then I read X-RAID nice features and bought another Seagte 4TB disc. I added it and wait that they "synhronize". And also this end up with only 1.6TB size for Volum C. I have inside 8TB, and only 1.6 TB is available. Is this a joke ? I shutdown and reboot the NAS several times and situation did not change. Then I install addon called forced expansion and what was written in the log "Successfully enabled forced expansion. The next attempted expansion or the next reboot will reflect this change." Of course I did reboot and hoped for the best, but again only 1.6TB available. :rofl: Of course I don't have any idea what is meant by "next attempted expansion" since in the web interface there is no option to access this process (e.g. to start/stop, monitor), so I assume that it should start during reboot. And further, with all this raidar and web nonsense interfaces there is no way to check or see if something is actually going on regarding running forced expansion. I can wait if the process takes time, but I have to see if the process is performing at all ... and when approx. it will end. I am slowly tired of this NAS, will simply take out this 8TB discs and used them in PC that I will change into NAS ...
does anybody have some advice or idea what is wrong and what I should do ?? before throwing away this NAS ??