I have forgotten my Sony xperia m dual c2004 pattern

I have forgotten my pattern of my device Sony xperia m dual c2004 and I have given my phone for software downloading but the repairing man is saying that ‘now your phone is waste and I contacted Sony service centre and told that the model has been closed so we cant help you' so guys I need your suggestions and answer me back I cannot use the volume up and down my Sony xperia m dual c2004 doesn't support these bootable option please help me. No one can unlock my device only one way is to remember the pattern………

PLEASE HELP ME