show the number

Unfortunately, if your ex is hiding his caller id information when he makes the call, the network never sees it. That means that there will be no link between his call and the private call you receive on the network side. If you were able to get his call log, then you might be able to match the timestamps of his outbound calls and the private calls you get. 

Drd3 wrote:

 Im trying to show that my ex exclusively calls me blocking his called ID so his number shows up as private number. tmobile rep says theres noway to tell the actual number that's called me and I've had several conversations with private number for the purposes of showing he calls me via private number exclusively how can I get this information from tmobile

You need to file a police report and they can then request that information from T-Mobile, if they feel it is necessary.