I've seen it happen dozens of times - maybe hundreds. Someone gets a kalimba with the best of intentions, they sort of connect with it, but they are afraid to really take ownership of the instrument - they doubt their own ability to tune the instrument. And so over time, their kalimba drops out of tune, playing becomes unpleasant, and the kalimba goes into the closet.
But I have also seen the opposite. I have seen people who doubted their own musical ability and doubted they had the technical skills to maintan their instrument's tuning. However, they so wanted to play the kalimba, that they overcame their self-doubt and connected with their inner musicality, trusted their ear, and successfully tuned their kalimba.
These sound recordings - where you hear me playing each note, properly tuned, slowly, from left to right, for some of our most popular kalimbas - should help you transition into successfully maintaining your instrument's tuning.