Why my pixel xl can't use vodafone sim

[AC Question]

I bought a pixel xl in hungary (I'm from hungary) and when I insert my vodafone sim card in it a notification appeared and it said that: "sim card isn't supported ask ee uk if this device can be unlocked". Can somebody help me what should i do?
Sorry for my bad english
Thanks in advance

 

[chanchan05]

Your phone is locked to EE UK. You can't use a SIM of another network on it. Contact the seller.