Or it could be that family and friends are telling you they bought your book when in actual fact, what they meant to say is that they meant to buy it but never got around to it. Sometimes people will lie and say they bought it cause they don't want to upset you.
I have to agree here I'm afraid - I also have book sales that I know FOR A FACT have happened and they are not showing up on my reports. I uploaded my 'masterpiece' on Hogmany (that's New Year's eve to non-Scots) and it went live almost immediately. I BOUGHT one myself to test the process and so far that is the ONLY one that has shown up on my reports. I know (again for a fact) that a friend BOUGHT a copy (and read it!) in the first two weeks of 2014 and I know her partner also BOUGHT one, her brother BOUGHT one (and just finished reading it last weekend - and enjoyed it immensely apparently!!), his partner also BOUGHT one. I don't believe these friends are lying to me! Another friend in Portugal also tried to download (BUY!) it and Amazon wouldn't let him - we're not sure why that was. I know Penny isn't lying coz' I saw it on her Kindle Fire last night! I checked my reports on 15th January ... nothing - just the one purchase I'd made. This afternoon I've followed a link from an email from Amazon telling me that they have just posted a new sales report for me ... still only showing my own single purchase! They don't show up in the "last 6 weeks sales" report ... so where are they? I can understand if they aren't reported until 15th February but why send me a message on 4 Feb saying they've posted new sales?
There is definitely something wrong with the sales report. I hope they fix it before payment is made or some payments are going to be short. It has nothing to do with gift cards not being used. These are sales that are definitely made but haven't been showing up this past week (that's when I noticed it started happening).
What about getting a royalty payment but your ranking reflects no sales? I look at my ranking nearly daily (it's just a habit) but nothing has changed, and today I got an email saying I was getting a royalty payment, and I was like "huh?" So, I checked my reports, and it shows I made a sale in the US (USDollars) but my ranking hasn't changed since August (not a big seller here). It's not that I care about my ranking, but it always at least jumps a little when I make a sale. BTW, I looked on Author Central, and it also doesn't reflect the sale.
I sent in a question to Customer Service and got a ridiculously long "canned" answer about ranking and other BS completely unrelated to my question (which is rather annoying) so I replied, asking again, but haven't yet heard back.