why did i get a message to say mobile data used when ive only just turned it on?

You phone is constantly using data in the background to update certain things. 

There are 2 mobile data settings you need to be mindful of on some phones. One is the general mobile data on/off toggle (found in the SIM settings area) and the other is the mobile data roaming on/off toggle (found in the mobile networks area).

Are you sure the message wasn’t an automated rate advice text saying you have a £45 roaming cap in place?

And when you wrote “turned it on”, was the phone switched off completely or in airplane/flight mode? Having said that by default our accounts have roaming enabled by default and if you'd set the roaming data to on before you left and kept the phone on (and not also in airplane/flight mode) then you would likely have munched through some data during the journey to the Netherlands and if your phone automatically latched onto Telenor maritime you may be getting an unusually high bill this month too.

Hello ​@DJ10b 

Thanks for getting in touch. 

One you arrive abroad, you will receive a text to confirm you are roaming. 

If airplane mode is not enabled and roaming is active, your data will be used on the handset for things like apps running in the background, email etc. 

Please let us know if you experience any issues and we will be happy to help. 

Thanks, 

Nat