Repeat of the same text message

I keep getting the same text message. It Sends two times each hour!

Text message reads “

Your automatic payment of $$$$.77 to Xfinity has processed - thank you. Review bill details here: https://t.xfin.me/834374D

TxtHelpOrStop

Msg&DataRatesMayApply “

please help how can I make this stop. I even text back STOP.