Geethika,
This was given as you deactivated live cache. I hope you maintained right back-up for the same for the first point.
a)All the transactional data even belonging to XYZ was deleted from the system.
For point two before loading it back, de-initialize PA and re-initialize planning area. Do consistency check for PA, MPOS & OM17 (DP time series) but after resolving next point.
b)While trying to load data in DP planning book , received error "key figure does not exist" and planning book could not be processed further.
Check in your storage bucket profile, do you have posting period (fiscal year)? Have you made any change for the same which is assigned to planning area? Check in OB29 for your fiscal periods do they exist in fiscal year variants. Example SBP is from 2011 to 2019. But fiscal year 2011 & 2012 is not available in fiscal variant in OB29.
c)While running the planning area consistency check , received error "storage bucket profile does not exists in the live cache".
Let us know if it helped.
Regards
Rahul