I once (pre-covid) had a 'buyer' bid on 10 of my items, and win......I sent a combined invoice.....she wanted to keep bidding. I had her phone number from initial transaction, so called her to make sure everything was ok with postage/weight etc....I spoke to her twice, as she bid on a further 9 items. 19 in total - sent her an invoice....ended up a NPB, her 'carer' rang me to notify that she was a compulsive shopper, and would cancel her ebay acount.....you just never know who you're dealing with!