Poor service

I placed an add with Looking for Spares to which Classic Motors North (Melissa Govender) responded. I was/am looking for a diff with a 3.7 ratio. Melissa contacted me as Classic Motor's have just the diff I am looking for. I made the payment and got the tracking number. Once the diff arrived I noticed that it is not the 3.7 ratio as requested. I contacted Melissa (this is two weeks ago) about the problem that I got the wrong diff. I have basically called her everyday, the story varies from they are getting the correct diff in either that day or the next and she will contact me and send photo's to make sure it is the correct diff. I called her just this morning again and again she said the diff came and it is in their storage and they will contact me and send me picture to make sure it is the correct one. I am still waiting!!!