Some Agencies Technology Is Old and Slow

I haven't been to an office for a while, but in the "old" days, people left voice mails on your desk phone and there was a business issued e-mail address.  If  the company didn't buy you a cell phone for work you could almost guess they were being used were used for personal stuff.  Like, call me on my cell phone, not on the office line because they might be hooked up to something where there was a record of the communications.

With government issued phones I'm surprised that there isn't a record of all communications somewhere and that they can't be recovered, and this would apply to text messages as well.

If extraordinary measures were taken to delete text messages, you can be forgiven if you think something is fishy.  In my old experience government computers were rarely state of the art so the erasure of messages might also be related to outdated technology.

The time involved with sorting the personal from work related stuff may be so daunting and overwhelming and add little to what is already known unless the targets of the investigation are already known.