Share your experience!
I now use a GiffGaff sim card into my xperia XA1. But when someone tries to call me
it goes straight on to the answering phone with the words " its not possible to connect your call"
How can I fix this, because I am missing so many calls
Did you contact your provider?
How is it in safe mode?
Did you test with someone else's SIM card?
Did you try to test your SIM card in another device and check if the same thing is happening or not ?