About six years ago, I submitted a short story (written in Cebuano) to a fiction-writing competition. The story details the hardships and psychological abuses I experiencing with my in-laws. The characters in my story resemble my in-laws and me and they were only identified in the story using first names (there are no last names whatsoever). My character's first name was changed but somehow has similarities to my actual first name. The story details their negative personalities (ina-under ang mga anak, lasenggo, etc.) and how my character and his wife copes with the situation.
The thing is this story won an award and was posted on the internet by the award-giving body. Eventually, my in-laws found out about my fictional story and are royally pissed about it. They are claiming that the story is libelous and now they are giving me and my wife a hard time even though we have been living separately from them for more than three years. They are even threatening to sue me. My reason is anybody who doesn't personally know them won't associate the characters in the story to them because no last names were used, and not everything in the story actually happened in real life because some elements in that story are purely fiction.
Can I be sued for libel?
Thanks in advance for any info you can provide me.