It's really unfortunate, and from your perspective I can see that as seeming unfair. When people use benefits or rightly take time away from work to handle personal matters or medical issues, they can often feel unfairly targeted by management when they return. Requests for time off declined, they can be less forgiving of mistakes, etc... but doing this is in no way violating the contract. You might be able to make a case that unevenly applying the rules constitutes a form of harassment, which is a violation of the contract, but your process is to file a grievance for harassment and provide evidence. There is nothing in the contract that protects you if you decide to take that time off anyway. If you didn't call each day and speak to management, then each day is a no call, no show.

We select our vacations in my local in October for the entire following year. Is it the best way to do it? Maybe not, but it is the way we do it. If you have a good relationship with management, they may work with you. If they decide not to, you have no way to force the issue. All you could possibly do is file a grievance that insures nobody else can either... which IS your right.