I totally understand your concern. I had a similar issue when I first moved to Medellin, Cebu. The best resource I found for accurate zip codes in the area is https://postalandzipcodes.ph/zip-code-cebu/medellin. Just visit the website, and you should be able to find the correct zip code for Barangay Medellin. It really helped me sort out my mail delivery issues, so I hope it works for you too!