Thunderbolt Duo

Bought a new 10TB MyBook yesterday and was promoted to activate WD softwares. Now my iMac is not reading the old Thunderbolt Duo and directing me to reformat staying “issues with RAID setting”. It was set as RAID0. Before activation, my iMac had been reading the TBD for years and even was able to extract some data when I first connect the new drive.

Any help would be most appreciated in resolving my issue as I can access my 7.5TB data now. TQ.