Failed D&C anyone?

Evin • Momma of twin🌈 babies.
We just found out 9 weeks after our D&C that it had failed. I've had some significant and intermittent bleeding so we had an US done that showed vascular tissue remaining in my uterus. HCG hasn't gone down below 5 either. I'm hovering just under 20. 
My MIL wants me to get a second opinion and my husband seems frustrated with the care we're getting as well. I love my doctor and have just assumed this can happen.
Has it happened to you? If so, what did they do? 
It's just terrible to extend this misery and I'm so very sorry this is something you had to deal with.