Printer wont print - headaches from HP

I bought an HP Officejet Pro 276dw printer in November last year. After installing the printer it wouldn't print large documents without issues. Took the printer back after speaking to online support. Replacement printer had the same issue. Found out that the printer is incompatible with Windows 8.1 (64bit), as printing worked perfectly on Windows 7. <br> Noticed there was a firmware upgrade today and updated the firmware, only noticing after I had started the process that you should not update over a wireless connection. No warning given by the installation program to this effect. Now printer is reporting all cartridges as damaged and needing replacement. <br> Got hold of online support Jack K tells me its a hardware issue (cartridges were printing normally 10 mins before firmware update) and that I have to take it in to a service center. Who is paying for my petrol and time? I have VITAL documents to print for tomorrow...and now I have to do this all because of a firmware upgrade? This printer has never worked properly, as advertised. <br> I would STRONGLY recommend avoiding HP. I have had nothing by unexpected cost and trouble from them.