BTDT many times, seen too many similar situations with regular bicycles, too.
If the first visit to the shop was due to owner abuse, likely repeat business for the shop if you just treat the customer nicely; who knows, maybe the person will buy an expensive e-bike from your shop in the future if you actually spent time with them explain the difference and find something that suits their riding needs.
Kill 'em with kindness and you may have a customer for life.