Fb in my iphone hacked. Also iphone hacked?

Hello

i am poor in english try to understand sorry !

i am using iphone xr with airtel network. But unfortunately my airtel network sms services are blocked . After 2 days of sms services blocked , my facebook account has been hacked and they get full access.

please help me i am very confused about this because either my iphone hacked or my fb in iphone hacked.

where it comes to fb, i’m not afraid to much but when it comes to iphone i am totally afraiding most important data stored in my iphone xr

And also i did factory reset my iphone. Is it helps?

please help me fast

Thank You