The Taco ZVC406 is very (and I mean VERY) easy to hook-up. I installed one just a few weeks ago. There are several wiring diagrams available on Taco's website, depending on the type of zone valve in use.
Yes, you have been ripped off. You have payed for something that isn't being used. Take a look at the diagrams and back-track what you have. You may be able to resolve this yourself...correctly.
Here's a suggestion. Get one zone working correctly and then replicate that zone for the remaining zones.