Laptop Notebook replacement

We bought a refurbished HP from Tech.co.za about a month ago. Soon after we bought it gave a number of problems. We contacted Tech.co.za and they at first tried to gave telephonic support, and then said that we will need to courier the notebook back to them. Soon after they contacted us and said that they will replace the Notebook if we carry the courier cost. The Laptop that they send to us is a similar model in a better condition. It it is running fine.