My mother needs a headstone

Hello everyone. My name is Mary, and I am looking for donations to give my mother a headstone for her grave. She's already been buried, but sadly she just sits there, in an unmarked grave. And it breaks my heart. My sister and I purchased together a stone from a website. But when I called the memorial park she is buried at, the woman told me I absolutely could not put it there. That I need to buy something local plus a 500 dollar registration fee for a stone. So now, I dont know what to do. I really just would like her to have something there, with her name. It's just a pile of dirt and rock right now and it saddens me to see. Mothers Day is right around the corner and although I know I probably wont be able to get her one in time, I just would like to try something now to get one there for her. She died pretty suddenly back in December from COVID. My dad, and my sisters and her brother were all there in the ICU with her when she passed. I will never get that day or any of those images out of my head. It was the worst thing I've ever had to go through and see with my own eyes. It just feels so broken and empty now that we don't have our mama here for us. Providing her with a headstone will definitely bring myself and my family peace of mind. Please, and thank you for any kind of donation you may be able to provide for us. It would mean the world. Thank you and God Bless.