emporia SMART.3 Mini locked screen

played about with the phone to try and set it up for my partner put the sim card from her other phone (payg from 3) hoping that it would transfer all to her new phone. seemed to doing things for a while but then screen message come. up screen is locked. took the sim card out again but message remains the same. I am going to change her provider to 1p mobile and have sent away for the sim card but have the feeling that the new sim won,t cure the problem. we are both 85 so probably that is the problem. HELP!

                                                    regards nev.