can we sue if they buried a stranger on top of our deceased family member without our consent? and if they moved her grave in order to make room?

family member passed aways about 10 years ago. we have the headstone but because parents passed away we decided to add their cremated remains on it as well. because of the time without a headstone her grave was moved in order to make room for another, it was pretty noticeable and also, i fear that they might/ve buried another on top of hers as well..