Canon MB2720 will not double-side print

[Julia1056]

I've just about had it with this printer.  Not only will it not double-side print, now it is just not responding it all.  Or it is telling me that the paper in the printer is not the correct.  It is correct. 

Also, will it not double side print 5.5 x 8.5 paper?  (That's what I want, but I can't make it double side regular letter size paper either.)

If anyone can tell me how to make it double side print anything, that would be great.

Unhappy with this product.

[Hector]

Hello,

Unfortunately, the printer is only able to perform duplex prints on letter and A4 sized paper. We can help you adjust the settings to resolve any error messages so you can print o letter sized paper. 

We would be happy to assist, but we would need some additional information to assist further. You can reply to this message with the information below and we can provide some troubleshooting steps or suggestions. For a more immediate resolution I would suggest contacting support over the phone at 1-800-652-2666. Our agents would be happy to assist.

1. What version of the Mac or Windows operating system are you using?

2. Along with the incorrect paper message, what error code do you see?