Oasis Spares (Oasis Engineering Solutions) - ******

I am based in Port Elizabeth and this company is in15 Top Rd Unit 9 Boksburg, account holder of the business is written Oasis Engineering Solutions, I bought a second hand intercooler for a BMW X3 2.0d for R2300 from them, I couriered it down to PE and it was not the right part, I couriered it back to them in Joburg and requested I be given a correct part, I am told they do not have the part, they do not refund, they will try and source the part from other Spares they 'work with', because I had tried to let them know of other spares that yave the part, I feel ****** by this business, because on the phone I am given attitude that the part is being sourced but there are no timeframes as to when I can expect it.

Please help.