So I dived deep into Google to find the name of this book I read when I was about 11-13 years old but I can't seem to get a grasp of the name. It was a book series about three girl friends who accidentally fell in a hole and met with a big talking frog who gave them some sort of missions or tasks to fulfill. There was definitely some magic to it. It is a children's or teenagers' fantasy book. The books weren’t big. I can't remember any more of it unfortunately as I do not remember the story or the author, but if I remember correctly it was a German author who was first published in Germany in the early 00's before being translated to multiple countries.
Thank you in advance!