There are a few things that can go wrong, for one thing the variety might not be hardy enough. I usually don't have problems with losing tulips but a couple of years ago I planted some frilly pink ones and most came up the first year but only one or two the second year. People here on the forum said they had planted the same variety and they weren't long lived up here. Also sometimes rodents get at the bulbs and eat them.

And if it's a cool and not very sunny location, or if they're late blooming tulips, they can take longer to come up. Either way, there's not much you can do to help them.

One time I planted a whole bag of tulips that did not come up, but the bulbs that I bought elsewhere and mixed into the bag did... I think that the bulbs that did not come up were diseased. They looked kind of moldy when I planted them. I agree with north spruce about being out of luck.
Better luck next time!

I'm in Calgary and all my bulbs have been up for a while (including those in the cooler sections of the garden) with a large number already in bloom. (I have, for the first time, some infected by an unknown soil-borne virus but that's another story.) Have you considered squirrels as the culprit in your case? If the bulbs aren't planted deep enough (should be at least 6 inches in this zone) those miserable critters will find them but you should have seen evidence of a lot of digging. They also leave behind the bulb skins. You don't mention where you planted them. Tulips have a hard time over-wintering in containers left outside and will rot in poorly drained soil.

The source of the bulbs could also be a problem. I've had a few friends buy those giant packs from CT/WM/other big box and 90% of them will not come up. The only big box store I trust to buy bulbs is Costco.

I agree, Costco tulips are fantastic! I have had mixed results from places like Walmart and Cdn Tire. Sometimes good, sometimes not.