Yes, because emojis turn a text message into a MMS message and these are charged for.
You can either use a different messaging app (WhatsApp, Facebook messenger, etc) or stop sending emojis.
There is a guide on how to avoid this on the community at the link below:
https://community.o2.co.uk/t5/How-to-Guides/Accidental-MMS-Sending-and-How-to-Avoid-it/ba-p/1014132
Please note, this is not customer services and we cannot access your account. Do not publish personal details (email, phone number, bank account).
Link to our guide on how to contact them can be found here
