SanDisk Ultra PLUS insufficient write speed how to fix

I have a SanDisk Ultra PLUS Class 10 80mb/s 32GB storage SD card that used to work well since I bought it in late 2012, but in the last few days, I’ve been getting the message on my video camera which is a Canon Vixia HF r700 “Recording was stopped due to insufficient write speed” after just 5 minutes or so of recording. I’ve tried initiallizing it and completely initilizing it and then I even reformated it to its default state, but I still get that dreaded message. I was told by a SanDisk representative that this SD card has a 10 year warranty, but I can’t find the receipt.

Of course, I could buy a brand new one for about $7 at Walmart, but it would be nice to try to fix this now.

What could I try doing next? What else do I need to know?

All help, tips, and advice is much appreciated.