Negotiating an offer, is it too late? - 3 months and counting

I received an offer as a call-centre agent and I think the pay is a little low. It has been weighing on me all week. The hiring manager was friendly and open. Did it backfire?

I thanked them and said I was excited but hoped we could talk about the pay. They came back with a bit more.

Ask about the range, not a number on its own. It felt more collaborative.