I have some antique collectible items on Offerup. I've had some really good experience selling there but this one it a PITA. She messaged me Saturday asking if I'd be open to offers. I said yes. She made an offer and I accepted it. We agreed she would come to pick up the following morning at 11. I messaged her an hour before and she said she was tired, could she come later in the afternoon. I said no. She agreed to come the following morning. She didn't contact me to confirm. this morning she made me a lower offer. I feel like telling her to stop playing with me but think I'll just ignore her. Are people like this serious or just entertaining themselves?