Mtn not onnering advertised benefits.

Contract upgrade on three phones and two data deals. The advertised 10 Gig on contract renewal was allocated on two phones, but one phone did not receive the advertised 10 Gig. Several enquiries were made, problem was never solved. We have been with Mtn for many years, with good service. Do not understand why one phones 10 Gig is not located as advertised by Mtn.