I searched and was unable to find a source supplying replacement parts specific to your needs. That your question has gone days without a response, indicates the problem is uncommon.
Approach a clerk in a local hardware specialty store. Ask about small diameter "round stock". Universally available in various metal types and diameter, find a piece of the existing plunger's diameter and cut to the appropriate length. Similarly, a length of equal diameter coil spring can be combined to replace the missing assembly. Some small nails might be the correct diameter, as another alternative source.
Or, you can go to a repair shop where they will fabricate a replacement for you. Either way, the door hinge is repairable.