Telkom false billing

I have a cellphone contract with telkom which i have faithfully been paying since it started. This morning (06.07.18) i wake up to a message that says "your service has been interrupted" so i called to inquire and was told in May my data got depleted and i started using from spending limit of R500 which i then had to payback. To the best of my knowledge i have never ran out of data and never got a text to say my data has been depleted. Now i cant have my account back and running because of this.