Offer arrived, can I still ask for more?, customer-service rep here

I want to negotiate but I am afraid they will withdraw. Thank you in advance. The hiring manager was friendly and open. Did it backfire?

Thanks for writing this out. I went through something close to it last year, and it got easier once I kept a simple log of every call and form.

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