Poor service

I brought a sony handset M2 aqua this year in April and the phone is giving me terrable headache now. It freezes and switch of by it's own. I then decided to take it to a nearest vodashop for repairs. But it came back still freezing and switching off by it self. I nearly lost my Job, our emergency call centre was unable to get hold of me, and i didnt realise the phone was off. Actualy they wanted to dispach me to an accident sence,since im a paramedic. I then brought the phone back to vodashop to be fixed again. Sony call centre called and told me that the handset is not faulty, from this number +***. Sony is ********