Tim is a 75 year old pensioner having suffered 2 heart attacks previously. Since being switched from SSE to OVO, he has received multiple computer generated unsigned letters demanding payment despite OVO agreeing to be paid quarterly. These threatened bailiff/debt collectors action, suggested meters had not been read, duplicate bills sent after payment...all false claims. Subsequently received debt collectors letters and visit for money he does not owe. After several letters to OVO, he received a letter on 21 June, apologising for their error 'due in part to change from SSE to OVO' and promising to put a hold on monthly demands as quarterly bills will be sent. This has never happened and threatening letters continue to arrive, causing severe impact on his health. He has never been in debt in his life and does not owe OVO for energy. His most recent quarterly bill was paid on the day of receipt. The threatening nature of the letters deserve to be investigated immediately and OVO should be held accountable for their false demands and the absolute shambles of their customer service/complaints department.