Pip backpay

Hi, I’ve recently got my back pay from pip. I rang up 14/2 about a change of circumstance and I got the decision on 21/3. I was on standard daily living and have been increased to enhanced daily living and standard mobility. I got my back pay through and they’ve paid £118. This is from 14/2 - 21/3 so 5 weeks. I’m concerned because this doesn’t seem right? Shouldn’t it have been more than this? I mean I’m grateful for anything but it doesn’t seem like the right amount.