unhappy customer

Yesterday i reviewed my data usage and it stated that my data is depleted, how can 50gigs that normally lasts me a month be depleted in 16days? i have not done anything out of the ordinary, please can someone contact me regarding this, i also see that my invoice received for July shows that i only get 30 gigs in total but my original contract is for 80 gigs. 50day time and 30 night time. the vodacom number is Cellular Number : *** CHANTE SWART and you can phone me on ***