TomTom has gotten a bit fussy about allowing new owners of refurb units to use the "Latest Map Guarantee". At one time, a new refurb owner could get it as easy as someone who had purchased a new unit. They "officially" changed their policy on this a few months ago and finally posted their tougher position on their web site. However, it never hurts to try -- give tech support a call. Who knows, you might even find a sympathetic ear and get a freebie, but it rarely happens these days.
To get the map version, press the satellite bars in the lower right corner of your main screen. On the screen where that takes you, press the small box in the lower right that shows your firmware version number. This will provide you with App 8.*** and your map version will be at the far right end of the line that starts with the word "Map:" ... it will be v8XX.XXXX for a 730.
Let us know what you find for BOTH your firmware and map versions and we'll help you sort out how far from current you are on both, if at all. The advice you get from TomTom Home about downloading a more recent map isn't always true.