I was offered a position at a job recently and was pretty excited. The offer was above the other offers I received at other companies so I declined the others and accepted this one. After verbally accepting I found out that the amount I was told was actually not the base pay but 10% above the base pay with a "performance review" bonus. I begrudgingly accepted knowing the constraints and downfalls but with a positive outlook forward.
Next came the most stressful phone call I received through this process. I was told by the recruitment manager handling this employment opportunity that HR thought I lived somewhere else and now that they know my real location they need to have a "conversation" about my salary. This is after me signing the job acceptance letter with my salary and everything else written out. The recruitment manager goes on to tell me that the place of origin they thought I lived has higher living cost and they calculate that in the salary for employment. Only thing is I received offers not much lower than the offer I received with the current company at the same location I live in. I also consult and have charged the same no matter what location I have lived in. I find this highly disruptive and it leaves a sour taste in my mouth. What should I do? Should I negotiate? If I should how should I handle this "conversation"?
Edit: People have asked in the comments how the employer was informed of the wrong location and I would like to update that the recruiting agency presented that information incorrectly. This position is also 100% remote.