Hi! They offer many ways to contact them, but one of them is by calling them directly at 1-800-375-5283. Navigate their interactive bot and then you'll communicate with a Customer Service Representative. You can also read more about it here: https://www.lawfully.com/resources/how-to-reach-a-live-agent-with-uscis

I try but I never talk to agent

When you call say info pass appointment you'll be connected to an agent

she say what kind info pass appointment need

say pending i485 when she ask for your receipt number say you lost it

thanks bro