Lowering my mobile bill

Hello, i am a long term xfinity customer and I'm wondering if there's anyway that my bill could be lowered. As it stands it is $415 and the reason it is this high is due to faulty xfinity internet connections, so neither myself nor my husband were aware that we were using the data. I understand that when you're not on wifi, it uses the data, but considering how spotty the connection has been, we don't think it is right that we should have to pay such a large amount due to issues on something we have absolutely no control over. Between my cancer treatments and supporting my family, this bill is huge and would cause great strain.