Data and airtime does the disappearing act

Would give them a minus review if I could.My data keeps disappearing,I called them multiple times.1st they explained that I must switch off background data.A lady literally went through it step by step.still,data disappears,within seconds.I dont use data during the day at all,yet my "data usage" is more than when I did. I buy whatsapp bundles,but at the end of the month I still have either whatsapp bundle left,but my data is depleted or I buy 2 whatsapps bundles for the month,as well as other data.I couldve actually taken out a contract phone with the amount of data I use.This is ridiculous.20 yrs of being a loyal customer and they cant even offer an explanation.I was told that Facebook takes up most of my data.I havent had Facebook since 2018!I dont even have the app on my phone.

Disgusting and seriously disappointing.Time to change my network.Would gladly welcome any recommendations.Thank you