Dog Bit Me And Owner Said Is Was My Fault For Not Reading Correctly!

So for some context, I am a 19 year old delivery driver for DPD and I live in the Netherlands.

Last saturday I had to deliver a package at someones house, like usual. I pull up straight in front of their house and start searching for that package, it took me a minute or two so my van stood there for about 2 minutes already. When I found it I closed my back door and I walked up to their house.

The people living there had a small house next to a bigger house, so two families lived on the same property basically. I noticed that they didn't have a front door like a usual house, instead you had to enter their yard (This is important for later) and ring their doorbell (Which was located IN their yard). I noticed a sign that said, "I'm keeping watch here", with a dog image next to it, I'm sure you know what I mean. I didn't see a dog in the yard so I wanted to enter their yard since I'm responsible for the fact that they have to physically accept the package from me, otherwise I am liable if it gets stolen. When I opened the little gate (The gate was about as high as my belly) to their yard I saw the dog barking and running straight for me, no big deal I've had this before and I went to close their little gate. The dog was really agressive and when I wanted to put the lock back on from the gate so that the dog doesn't escape, it jumped up and almost bit me in my face, I immediatly bounced back but the gate was still a bit open. I tried one more time to put the lock on since that was my only defence against an agressive dog but this time it went straight for my hand, and it bit me. Only then did the owner come out the door, so it has been 3 minutes since I arrived. I knew the dog bit me but didn't look at it yet because I was still in shock. Then the owner said "Calm down", still don't know if she said that to me or to the dog but the dog was still barking like crazy. She walked over to the little gate and I gave her the package, then I saw my hand covered in blood. For the next conversation we had I will refer to me as "Me" and to the owner as "ADO" (Agressive Dog Owner).

Me: Ma'am, I am going to make a report about your dog biting me! ADO: There is a sign here (points to the sign I mentioned earlier) that says our dog protects our property, so it's your own fault. Me: Well your dog isn't allowed to bite anyone, regardless the situation. And it deffinetly wasn't my fault, you want your package right? ADO: Well then you should read the sign next time! (Keep in mind, my hand is currently still bleeding). Me: In that case you will hear from me soon and I walk back to my van.

I noticed that the dog punctured deep into my hand with one of his teeth. I immediatly search for something to wipe some of the blood of of my hand and I noticed my hand is swelling up. Once a majority of the blood is gone I call my supervisor to tell him what happened, he advices me to go get some first aid. I walk into a restaurant nearby and they let me use their restroom to clean my wound. After that they give me some Band-Aids and they ask me what's going on, so I tell them and they are discusted by how she treated me.
Once back in my van I call my boss and tell him what happened and that I want to go home and see a doctor because you can get some nasty infections, he tells me ofcourse and I go home. (At this point I still had to deliver several packages, but I gave those to a co-worker.) Once home I immediatly go to the emergency room, luckily they didn't have to give me a tetanus shot but they did give me antibiotics which I have to use for a week. The doctor said it is a very deep wound and he could've easily taken some flesh of my skin!

Since I am discusted about how the owner treated me and said it was my own fault I really want to press charges, I hope I can work again this week because I am a student and I also need to pay my bills, I had to go home early plus I get extra bills for the emergency room visit and medicines I have to use! What can I sue them for?