Depends on your lease.
Check your lease and see if that is permitted. It may not be. (Often, a lease will provide that there must be reasonable notice.)
So: Read your lease. Then, contact your landlord. If the lease specifies that reasonable notice must be given, explain to the landlord what happened. Whether the landlord has listed the home for sale or for rent, it's possible to put in the "Comments" section of the listing a statement that certain notice must be given. And even if your lease is silent on that point, request that reasonable notice be given.
One other point: You say you videotaped them "looking thru my stuff." That wouldn't be permitted in any case. They would be allowed to come in the house. They would be allowed to open the refrigerator and kitchen cabinets, for instance. But they wouldn't be allowed to look through your personal possessions.
Tip: Here's a great argument for reasonable notice. Use your own language, but: "I'm glad to cooperate with your efforts to [sell or rent] the property. However, though I do try to keep the place presentable, I think it would show a lot better if I had some notice. That way, I could tidy up a bit and your property would be a lot more appealing to anyone looking at it."
Hope that helps.