User Activity

I sold an item at auction last Sunday. I have messaged the buyer through eBay and sent an invoice however I have not had any communication from the buyer. Any suggestions as to how to move forward? (the item is for pickup only) Thanks
Can I change my seller name and keep my feedback score? Or, will I start from zero?
I am not missing any money from my account but every so often I get these emails. They vary in amounts from $15.00 to $200.00