NSA320 button broke need to restore data from the disks

Hi
Sorry I'm new to this!
I have a NSA320 and when i turned it on the power button broke. I bought an NSA326 thinking I could put my disks in that but I have been told by Zyxel that they won't work and there is nothing I can do.
The data is too important to me to lose it and the disk were working fine.
I've seen various posts about Linux and restoring from RAID but although I'm an ex I.T engineer I don't know too much about either of them!

I really need a solution as I can't lose my data.
i've considered buying a second hand NSA320 just to get my data back but want advice before wasting any more money!
Any advice would be gratefully appreciated.

#NAS_June_2020