Re: I predict the response
It will end up being the exact same vendor again.
1 They are already a trusted vendor, so it will be easier to hire them again rather than get a new vendor vetted and added to the trusted vendor list (much less paper work).
2 They are the people who are most familiar with the systems and the problem, which mean that getting up to speed will be fast and fully understanding the systems will be negligible compared to bringing a new vendor up to the same level of knowledge. And they are already familiar with all the internal billing and reporting systems.
3 Problems just like this (<insert problem name here>), were already included in the initial budget request for the overall project, if they changed vendors that would initiate an investigation, red flags would be raised and a whole new budget submission would be required. And no one wants that level of paperwork.
So it will be the people who caused the problem who will typically be tasked with fixing the problem. In reality there is very little incentive not to screw up, screwing up gets extra money for a vendor.