The issue is, what is meant by "botched up":If they followed all instructions and the headstone is of acceptable commercial quality, then you would have no cause of action: you can't sue someone simply because you are not personally satisfied, if the product (the headstone) is as more-or-less good as the average product (headstone) out there.On the other  hand, if the headstone is below generally acceptable commercial quality and/or they did not follow your instructions, when you may well have a legal cause of action.