Did you test the card before using it? There are a lot of "fake" cards out there, and the usual advice is to only buy from known, reputable retailers (and never anyone selling from eBay), but even then fakes sometimes get into their supply chains. Usually those things allow you to put a small amount of data on (say a GB or 2) before you start suffering data corruption (because they are really small capacity hards hacked to look like big ones), but if a new card is misbehaving then testing the card is both what it claims to be and is working properly is the first thing I'd do.
If you have a windows PC and a card reader you can use an app called h2testw to check the card's real capacity. An Android app called "SD Insight" can be useful.
It's certainly worth testing the card with a computer and a card reader, just to see whether it works in a different device.