High Data Usage

I switched to Xfinity internet from CenturyLink last October. My calculated data usage is much higher now than before I switched. I was never close to the data cap like I am now. My streaming & internet usage hasn’t changed. I don’t do gaming. A neighbor with Xfinity internet has much lower data usage. We both use the internet in a similar fashion (streaming, email, etc). Can my usage meter be checked for accuracy or can you tell if there’s a “data leak” or which device is the culprit? Thanks.