...but I used water from my LFS to get the cycle started yesterday...
I hate to add to the pain, but if they told you your tank would cycle in a day using water from a cycled tank, then they took you again. The bacteria you need for a cycled tank is not very plentiful in the water itself. It's in the filter, the substrate, on the plants. The best way to jump start a new tank is to use a filter from a cycled tank.
However, the last filter I would use is one from a LFS. I'd also use their water as my very last resort. They get too many fish in and out which exposes them to more diseases. Given that most LFS use a filtration system that's all interconnected, if they get one batch of fish with a parasite, fungus or bacteria, it's then exposed to all the tanks. Sure, they probably use a uv sterilizer, but they are not 100%. It can only sterilize the water that's directly exposed to the uv light.
I hope the LFS is offering misguided information only because they are truly ignorant and not as a malicious attempt to have you keep coming back to fix problems you may have.
For example, if you cram a bunch of fish into an uncycled tank, then the ammonia, nitrite and nitrate levels will cause harm to the fish. The new fishkeeper sees his fish are getting sick and will run to the LFS for medicine. Then, if the medicine doesn't work and the fish die, what does the fishkeeper do? Runs back to the LFS for more fish! And the money keeps rolling in.
Do you have a Freshwater Master Test Kit to test the water? I'd strongly recommend using the liquid/test tube type instead of the quick test strips. The strips are not only more expensive per test, but they are much less accurate. You need to keep a very close eye on the ammonia, nitrite and nitrate levels. How they increase (or not) will tell you where in the cycling process your tank currently stands.
Since your fish are already well exposed to the water from the LFS, ask them for a handful of their gravel. Put that in some kind of netting (pantyhose works) so it won't get mixed in with your substrate (for aesthetic reasons). That will help to seed your tank with the bacteria it needs.
I'd also double check their fish warrantee.