Hi, what was the reason for changing your sim?
Do you wait to see if your new sim was working and then change the number on your account?
Which phone do you have?
Do you see signal bars and a connection symbol
(3G, 4G, H, E, gprs)
From your phone keypad dial
Star 100 star 7 hash
And press call
Do the same with *100#
(repeat those several times)
What word or words do you see on the phone screen?
What do you hear exactly when you call your new number from another phone?