Help with new phone connection to PCM 3?

[DJMC]

Cayman 981 2.7 May 2014. Has phone prep (and telephone module, but irrelevant).

Was using an HTC One X plus with no problems. All my phone contacts showed on the right hand screen list.

Now upgraded to Samsung Galaxy S7. All contacts have transferred over to the new mobile. That in turn is sync'd with the car.
However, not all of my contacts show in the right hand screen, only some of them???

Suggestions?

I phoned Samsung and they suggested getting the car's software upgraded (yeh... at £400!).

Maybe I need to delete all the car's phone stuff and start from scratch, but how do I do this?

Thanks for any help.

[edo]

I'd def look to start again; go into phones in car and delete them, or even reset PCM.

Can you see a patter to the missing ones; one end of the contacts database (too many?) or certain types; are some Google, some on the phone etc? It's very rarely just random.

Might also have been interrupted but not resumed.