where do i go to find out when my contract with dirtectv is up

To find out your service agreement date, you must call DirecTV. Since the most common reason for somebody to want that info is because they are considering cancelling, they want a live agent to discuss the situation to see if they can retain your business (just like any other company). When you call and get the voice system say "cancel" to get you to the correct department.

If you compare the prior bill to the current one, what do they show? What are the differences? Check for ending discounts, one-time charges, past due, etc. that may explain the higher cost. But if that doesn't clear it up then of course ask the agent to go over the bill with you. Or you could post a screenshot of the bill for other experienced customers to help make sense of it. Just don't post any personal info (like account number).

You have to call them to find that out.

This is a customer to customer forum with no access to any accounts, look at your previous bills to see what changed most likely a promotion ended.

When you look at your bill/invoice it will show you your promotions of course. But it will not list the service agreement itself. That they have never listed online for the reason I explained above.