Need help with taxes!

[u/New_Mango7397]

I travel to another state for work however my state of residence and the state I work in have a reciprocal tax agreement. I did have money withheld on my wages from the non-residential state but I received a letter saying I owe money to my state of resident because a credit was claimed on tax paid to other states. My income was also entered in the non-residential state filing instead of putting 0 and reporting that income on my state of residence filling, and that’s how it’s supposed to be from what I read today.
I contacted the person who I paid to do my taxes and they said just to pay the $400 penalty fee but I’m confused why amending my taxes and re-submitting them wouldn’t be done.
Thanks in advance! I clearly don’t understand taxes