Do you get an itemised bill, either in paper format or online? Start there and see if you recognise the calls. You also need to check who else has access to your 'phone during the day.
What is ransomware and how do I protect my PC from WannaCry?
What I learned from my mentor, Oscar-winning VFX supervisor Phil Tippett
Siri vs Google Assistant
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.