Jig-jag is Verges slang for shoddy craftsmanship or something untrustworthy. Not up to standard.
Origin
The term comes from the old coins of Jigarta, the Jigarti Gildan. These were called jiggies for short. The coins were cheaply made and easy to counterfeit. In fact, at one point there were said to be more fake ones than real, and they ultimately became all but worthless.