Job not responding after pay negotiation

Got an offer with a start date and pay. I was ready to accept, but requested a 5% pay increase, which is not uncommon in my field. The person coordinating my hiring has not responded after that, and it's been a few days. They always responded instantly before, and I know they're on duty. What should I do? I don't wanna sound forceful, but that's disrespectful to just ignore me and not communicate. Even if the pay is firm, they should say something. Even if they need time to figure it out, they should say something. Technically at this point how do I even know the original offer is still valid so I'm really annoyed.

What makes it worse, the timeline is sensitive because I'm supposed to start in less than 2 weeks. The work is at the same agency where I work, just a different dept. Should I try to contact a different person? I don't want to come off weird, but this ambiguity is dumb and stressful. I don't mind accepting the original offer, but I need to know what's going on.