e problem is the memory card. I had the same problem years ago. I bought the Samsung 64GB PRO SDXC Memory Card - Class 10 (MB-SG64D/AM). You can find it on amazon.
Try this card. I had the same problem before. After I bought this card my problem was gone!!!!! I have the canon 70D too.Here is the link:http://www.amazon.com/Samsung-64GB-Class-MB-SG64D-AM/dp/B00IVPU6BY/ref=sr_1_1?ie=UTF8&qid=1437632569&sr=8-1&keyw...
I bought a new memory (Samsung 64GB PRO SDXC up to 90MB/s class 10). It's working very well and I have no more problem. My problem is gone!!!! Finally!!!!! Buy a new memory!!! Try the same that I bought on Amazon. It's about $50.
