The prize is part of MTN's 21 Days of Y’ello Care campaign.
The telcos' revenues increased marginally by 4.2% to $392.3 million.
Africa’s biggest mobile network suffers a loss in users for the third quarter.
Zimbabwe's biggest mobile network works to improve service with a new contact centre as well.
Research body says state-owned companies, lack of competition is throttling the market.
Potraz wants the Zim telcos to charge 9 cents per minute for voice calls by 2016.
Mobile operators and the telecoms authority have joined forces to regulate fake mobile phones sold on the black market.