Jio — false data usage calculations

I very strongly feel that jio is cheating it's customers by not providing adequate data as per recharge plans. I'm a jio prime member and have opt for rs 555 plan of 86 days with 1.5 gb data per day. On 8th may'20 i started downloading a movie at around 10.30 pm and by 10.43 pm a message came reminding of 50% data usage and by 10.56 pm i. E. 13 minutes later i was reminded of 90% data usage and 3 minutes later my data got exhausted. During the entire time the movie got downloaded only 248 mb and it got cancelled after that. How is it possible that from more than 750mb data only 248mb can be downloaded and the data get exhausted.
I promise not to use jio if this problem continues and would rather shift to airtel after my recharge is over.