Your Airtime balance is low, would you like Xtratime Loan?

Please help.

I'm receiving a pop up message stating "Your Airtime balance is low, would you like Xtratime Loan?" I select No each time but the same message keeps returning.

I've tried sorting out the settings and send sms-es. It keeps the screen on all night.

NO, the answer is NO.

Please help me sort this out, as I can not find any other guidance on google how to stop it.