Printer damaged

I bought an hp printer at the shop. Where they never explained how it's warranty works. Because it was written on the box that the printer has a 3 year warranty I took it like that. Before the warranty lapsed I had a problem with the printer, I then took it to the shop. The technician asked if I registered for the warranty to valid? I told him no one explained that to me but I remembered that before connecting it I registered with hp. He then said they need a proof of that which I provided. They took the printer and said it would take 20 working days for my printer to be fixed which that was in December 2014. Up to date I don't have my printer. I called the shop and I spoke to the store manager who apologised and said I must come an get a new printer which I went. But the printer he was giving me had a problem of catrrages, they are not easy to get. The store manager promised to order for me he failed and I then said they must just fix my printer. Only to realise that my printer is still at the shop not attended. My business is suffering because of this.