Changed Gig terms in the middle of doing a Gig

***Update: After messaging Gigwalk they paid the gig for the completed work and didn't require revisiting the location. The right thing to do all along! Thank you.

Why would I be responsible for revisiting a Gig location (after completing a Gig) if the visit times and questions are changed after I accepted the Gig, finished the Gig, and submitted the Gig? I did everything that I was supposed to do and then the conditions for payment are changed? You should not withhold payment if the work was completed correctly and on time.
Has this happened to anyone else? This was a Taco Bell audit.