Data drank redbull

I am operating prepaid for years now i have always believed mobile supplier is the biggest money making schemes in the country. Besides that to come back to my complaint.i have an emergency i need to use my dell laptop to send a mail using my hotspot on my p9 lite and connect on wi fi. Now i have about 700 meg of data on my phone it got depleted with in 2 min of being connected now this mail being urgent i buy another 1 gig of pre paid data it got depleted within the first min of being connected my laptop is running no updates and not connecting to the internet there should be no reason that my data or almost 2 gig data gets used within the first 5 min of using gmail how is this possible but yes i can expect this i believe **************** is normal from you guys.this is me being ****ed off and completely dissatisfied.please let my know how this is possible. My **********