Every other month or so, we get a harried call from someone wanting our help in “getting their molds” back from their Chinese product supplier. Chinese manufacturers commonly refuse to return molds to foreign companies that switch manufacturers. The Chinese manufacturer holds on to the molds to extract money from the foreign company or for revenge. This is very common.
Getting molds back at this stage is difficult and expensive and not always possible. In other words, if you do not want to lose your molds, the key is to avoid getting yourself into this sort of situation in the first place.
The way to avoid having your Chinese manufacturer run off with your molds is to put in your China Manufacturing Agreement a provision that makes clear that the molds belong to you and what will happen to the Chinese manufacturer (liquidated damages) if it fails to return your molds to you.
Even better, you should, if possible, get a deposit for your molds, which deposit you will return when your molds are returned to you. If the Chinese manufacturer will not give you a deposit for your molds, (most will not), put in a liquidated damages provision that applies if your mold is not returned when specified. That provision alone goes a long way towards taking away the incentive for your Chinese manufacturer to hang on to your molds.
You want to keep those molds for which you paid? Do something about it now, not later.