I tried one of the HF cheap grinders and wouldn't even give it to a friend. I threw it away.
You couldn't give me 1000 of them to replace ONE of my dewalts. They're simply an inferior product. They're nowhere near the power, and just about worthless even on the lightest of tasks.
I think you wasted your money. Your expectations may be a little lower than mine. I expect the manufacturer to stand behind their stuff for more than the time it takes me to lose the receipt.