My outside fiberglass door was stained several years ago. It now has lots of bare spots from shoe/boot toes hitting it and also being bumped when carrying packages into the house. I want to restain it the same color. How do I do it?

Cannot find a professional in my area to restain and finish my front door. A friend (carpenter) did it for me. He tried to strip the old stain, but was unsuccessful. Instead; he painted or used a primer of some sort – then, used gel stain over that. He polyurethaned