Verify what movement you have in there before you start looking for replacement movements or reaching out for repair services. I had one of these a few years ago and it had an odd movement. It was an ETA movement but it was a tiny one most likely for a female watch size. Here's some pictures of it below. I unfortunately don't have any clearer shots of the balance to see what caliper number the movement was. Might be able to locate the old sales thread or the text I typed in Google docs for the sale.
I’ve got one of these in my endless array of “to work on” items.
Mine is the same story as the images above - mini ladies’ ETA movement which means the brass spacer can be drilled for dial feet for a gen dial if one is so inclined.