refund not happening

Hey my name is joe smith and i want to lay an complaint about the bad service i have been getting over a year now i brought a engine vorm boston engine on the 18 3 2014 when ghey deliver it off it wasnt the right one so i contractbthem and told Azel and after two week he came to collect it , when i contract Afel about the engine he said i must give him time for the new shipment to come in and i said that fine, when theshipment came in they still didnt have the right one thisnhas been going on for to long now. Everytime i phone him he keep promising me it coming in, so i gave him a time and them on the 13 3 2015 i called him and he ask to give him just aweek to vet it, a week went by and he still didnt get back to me, so when i called him he said they would refund me the money back that was on the 20 3 2015 and i am still waiting for my money please help me