hello, welcome!
online places might be a better place to try, my dude is from Under Ground Reptiles, their stuff is captive bred but I've heard the costumer service is not too great. if your not comfortable with shipping, Facebook's a good place to look for breeders in your area. Do plenty of research about the people your buying from as well.
As for your guy, i'm sorry he passed away, sometimes parasites are the main cause for sudden deaths like that, you could take fecal samples at some points to have a vet check it to make sure your frog is doing okay.
hope this helps!