Western Union Did a transfer of my 550 to someone which I don't know and the person wrote my middle name wrong but they gave that person the money now they said they can't refund my money back. I've got all their Internet

I'm just writing to report an incidence that has happened to me since the 1/08/2012. My mum did a western union to me in Harlow town UK. At 15:32 and someone else has collected it in my place western union has done their investigation then emailed us their outcomes saying that the money was sent at 10:34am and the person has collected it at 2pm which is wrong plus the person wrote my middle name wrong they still gave the person the 550 which was sent from my mum from Harlow for me to collect in Uxbridge UK. Western union concluded their investigation saying that that they can't pay that money back to me because they claimed that I was the one who collected the money . That money was collected at Manchester but they said they can't provide me with any ID which the person used or even the address where the money was collected.

I really need that money I'm only a student and I don't work that money was the only money I had this has happened since the 1/08/2012 Manchester police have just closed my investigation without giving me the right reason. I don't know who can help in this matter.