My prong collar recently broke and can't find a replacement part for the area that broke. What should I do?

Several years ago I bought a stainless steel micro prong collar to train my mini schnauzer to quit barking and pulling. It worked so well when I got my doberman I ordered extra links a month ago to use with him. Well today while in the car, the collar broke. I was told by my trainer to use the prong on him in the car to correct his whining and howling (excited, not nervous). So this is what we did and the chain part, not the link part just broke. I tried to look and see if there were other people that had this same problem, and found a few on the web. I cannot find a replacement for the broken area and I am not sure what to do. I have to take him to class on Wednesday and would like his collar to ride with him in the car. Not exactly sure the corrections are working, but I am trying to be consistent. Please let me know what I can do to get the collar fixed. Thanks.