I had an experience where a customer purchased software (about $400 worth) and then after 2 months claimed they never received the email containing the license

I had an experience where a customer purchased software (about $400 worth) and then after 2 months claimed they never received the email containing the license keys. I attempted to email them through many various routes (eventually from my own google and ISP accounts, even) but they kept claiming they did not receive any email from me. I don't really know if this is true, but if it is, they have the most aggressive SPAM filtering in the universe since I have never experienced this from any other customer. In the end, they issued a chargeback and told VISA it was fraud, and the payment processor, ShareIT refunded the money. ShareIT is pretty expensive, but I must say they were very good about it - they communicated with me directly (real humans), seemed to understand the situation and have not held it against me in any way (as far as I can tell). (no particular point to this, just thought the story might be interesting to others.)