Few Issues
Everything have been done. Site is almost done. Just few issues.
Job A had to been done and Job B had to be done.
Not Complex
As WordPress Developer, i do get email where clients aren't aware about complexity of the job.
I think its just honest mistake when client says something like this. Maybe they aren't aware how coding and development works.
Case 1. Yes the client maybe right. Its just a minor changes.
Case 2, which is the case in most of time. Those changes turns out to be the most challenging one in the project. Good chance previous developer wasn't a good coder or someone who is just trying hands on WordPress customising a premium theme.
These were case that happened to me fair few times. And this is the reason i barely take on any job done by other developers.