Sorry to read of your predicament
I worked for Telstra for nearly 9 years until recent.. Is your mobile on a personal or business account (2 different billing systems)
If Business they can do a screen dump of calls made, time & location but its 24/48 hours behind.
If consumer, well you should be able to log into 'my account' via Telstra website
All the above will only prove sadly is you didn't make an outgoing call - not that you didn't receive one
Telstra does not record incoming call details UNLESS you report your receiving unwanted calls (stalked etc) then they will place a trace from when you alert them..
600hp Blown Maloo