Hi. Im getting warnings on my phone about it using 3G, and warning that 3G is going to be turned off
Warnings via txt & a warnings when I try to call someone 

My phone is 4G & I can see it connected to 4G+ (the 4G icon) . In the phone settings 4G preferred is selected
Is this just a mistake or something else going on ? 
I am considering a new phone , but not a good time at the mo, too many bills to pay .
Cheers