ensure IT Repaired HP Printer - still not working

Dear HP<br> <br> I purchased a HP Deskjet 2545 Ink Advantage on 28 July 2015 from HP Sandton City, Johannesburg.When I got home I put the cartridges in and tied to print. The printer was printing half of the the letters contained in the document. I took it into the shop and they told me that the ink was finished as the cartridges they gave me were test cartridges and I needed to buy new ones. I purchased new cartridges and one again when I tried to print the same think happened. I went into the shop again and they took the printer in for about 7 days and the company who repairs on behalf of HP (ensure IT Services Pty. Ltd) told me that they printer head was faulty. after some time they eventually returned the printer to me and said it was fixed and I received it on about 27 October 2015. I tried yesterday to print and once again the same problem. I went into the shop today and Muzi had a look and said that the cartridges need replacing. I was astonished and said how can that be when my computer shows that they are full and I have hardly used them. Muzi and a colleague said adamantly that if you don't use the new HP Printers often then the ink cartridges dry up.