For iPhone users, please note that you will be charged by Apple's activation request# sent to Apple Servers (in UK) each time you
- Turn on/off iMessage
- Turn on/off FaceTime
- Turn on/off iCloud
- Insert SIM card into iPhone (Removing and re-inserting will also trigger activation requests
Your iphone/ipad devices would have prompted you for this charge.
#Activation request is sent via international SMS @$0.30 to Apple Servers; including but not limited to the UK numbers starting with 4479xxxxxxxx
For more details, you may check out the dedicated Apple Support Platform https://support.apple.com/en-ph/HT201349