Sorry Peach, but the basic rule is:
You installed the blinds, attached to brackets attached to the wall. The blinds then became part of the property owned by the owner. hartman (aka a million other names, for who knows what reason) cannot reason this far. His mind is too small.
Now, you may ask, how can they be his property when you bought them?
What happened is that the blinds, brackets and all, are no longer in the category of personal property. They are now in the category of fixed, immovable property, also called real property. The blinds belong to the real property. The new landlord bought the blinds along with the rest of the real property, regardles of who purchased them.
My suggestion is that you discuss the matter with the landlord. Point out how you will remove the brackets, the holes, everything, even think about providing him with some substitute window coverings, but cheaper ones. Even though, by law, he is entitled to the now-attached blinds, you can try the argument that there were no window coverings when you moved in. See what you can work out with him.
But in the end, the blinds actually belong to him now. If you take them without consent, you are no better than hartman, and he is basically a thief.