I friend of mine had an SD card he ordered from eBay. He said it was 512 GB, but I doubted it. I searched the web, and came across USA Discount Warehouse. They had a 512 GB Micro SD Card listed so I bought it. I wanted to see it for myself because I was not aware of any Micro SD Cards of this size. The card did not work, and stopped saving data before it reached 300 GB. I emailed them TWICE before they responded. Tonya Bartow emailed me, and offered to refund my purchase. Of course you do not receive a full refund because they keep the shipping fee. Tonya assumed I was going to use this in a smart phone. I explained how wrong sahe is. First I dropped some knowledge on her. I explained there have been prototypes for 512 GB in 2015, and a theoretical 1 TB prototype in 2016, but none of those are ready for market. The card they sent me was going to be used in a Nintendo Switch which supports a maximum capacity of a 2 TB Micro SD Card. That capacity is four times greater than the card in question. I mounted this on my computer first to test the capacity/efficiency, and not only did they sell me a product under false-pretense it is also very slow. This card is not as advertised.
To give further insight, there are a lot of these Micro SD Cards coming from China. They flash the card to fool devices into believing there is more space than what is available. The average consumer will fall for this and lose files when the card has reached capacity. The constant attempts to save more data can cause items to become overwritten, or corrupt.
Contact your bank to reverse the charges, then demand an RMA from this company.