Hi David,
if you have process chain data flow design of your data flow then please old logs and see.
mean while take basis team help(SLG1) and track logs which are happen on your bw server in particular time frame.
so that we can find the user who done manual deletion by mistake.
To activate dso data, go to your DSO-->manage-->request tab-->select all requests(inactive requests) and click activate icon. on next pop up screen, select do not condense requests while activating and execute it.
Thanks