You can always setup ePrint on your printer as a work around and if emailing the document to the printer prints normally, then it is not the print functions within the printer itself. I am still researching this for a resolution but I really want to know a few more things first.
1. Has any document ever printed properly? I see you mention Pages worked so perhaps it is the document you are printing?
2. Have you ever been able to print successfully to a different printer using the same document or app?
3. Does this happen using the ePrint app? I strongly suggest using the ePrint app and printing to your network connected printer or even setting up ePrint and sending it an email. This will help determine if this is a problem with the printer or the iPad.
It sounds like you could possible have the wrong paper size selected but that is not typically the nature of printing from two different apps. If you only have a few more days to decide, I am afraid this is a very rare issue that even Apple Support doesn't have documentation on. Answer those questions for me please and by this time hopefully I can help you fix this so you can keep your new printer.