I have a client. There was one specific limitation of the solution we were implementing. I made sure to tell him about it, and he said it's fine.
Now later when it's implemented that way, he feels, it's not ideal for him. Overcoming this limitation would require redesigning the current work, and do things bit differently, and it's quite lot of work.
Since he feels he has not got what he wants, he wants me to do the necessary changes now for free.
But I feel since his requirements and needs have changed after we agreed upon everything, I should not be liable to do free work for him.
I am also wondering what's the best way to approach him. I am thinking of sending him the screenshot of conversation where he agrees he is fine with the limitations.
And also write him something like this:
Hi X, As you can see I told you about the limitations before, and you said you are fine. Now these new changes will require drastic change in design and will be a lot of work. I feel it's not fair or reasonable to ask someone to do free work for you if your requirements change later. I hope you understand. Thank you.