MTN SA will take steps to prevent the grey routing of voice calls to its customers. 

According to the company, this is in keeping with international standards and practice, andis designed to prevent fraudulent routing.
Grey routing bypasses interconnect relationships by rerouting voice calls obtained on the wholesale market to users.
"The most noticeable impact on our customers is receiving international calls of very poor quality to the point our users cannot hear the other person," says an MTN statement. "Additionally, grey routed calls do not deliver CLI which mobile users value in managing contacts and answering calls.
"It also affects the people calling MTN users with the same poor quality and they find it very hard to get through to the South Africa user due to the low call completion rates."
MTN believes grey routing also undermines delivery of roaming services to inbound and outbound users. Inbound roamers cannot receive calls that have been grey routed and South African roamers overseas have difficulty accessing voicemail and other services due to the poor quality and lack of CLI to identify them on the network.
Tim Lowry, MD of MTN SA, comments: “Internationally, grey routing is illegal and MTN cannot compromise the network quality for its customers.  We are in the service business and ensuring a top quality network service is a key priority for us.
“Grey routing congests network cells and prevents legitimate users accessing the network are costly to maintain and have caused a serious degradation of quality calls to the MTN network and an adverse impact on international roaming services. These impacts have caused customer complaints from MTN and international customers and income losses to MTN.”
MTN will suspend services found to be used for bypassing the legal interconnect routes to MTN or other networks. MTN has also notified its interconnect partners to stop their networks being used to grey route traffic to MTN.