The only other option I see is to make it a cold cream, and throw any unused portion out after a few days. Goat milk and water create a BREEDING ground for very yucky things to start growing... As you see in your "experiment". You either need to find a way to get a broad spectrum preservative shipped to you (a REAL one, not a substitute), quit making lotion that you expect to be shelf stable, or make them to only last a a few days in refrigeration. There is NO substitute for a real preservative.
~ Rachel ~