There they would have the phones charged at the homes of sympathetic residents and run back to Malolo in the evening. Their payment? A banana or a paw-paw.

But this exhausting exercise came to an end when a group of South African farmers saw the youngsters' daily struggles.

"These farmers just laid an electric line to an old woman's house. They developed, in an hour or two, a cellphone charging bank with about 40 plugs at which the local community can charge their cellphones," said Theo de Jager, vice-president of AgriSA.

De Jager and Andre Botha, President of Congo Agriculture, have been in negotiations with the Congolese government since its invitation to South African farmers to bring their expertise to the country.

Thirty-nine farmers were lured to the Congo to bring food security to the country.

Everything has to be imported in to the Congo - a 6kg box of practically rotten tomatoes, for example, costs about R700, according to De Jager.

The state made 85000ha of farmland available to the farmers, of whom 13 have moved to the country on a "semi-permanent basis".

Thirteen others commute between South Africa and the Congo every two weeks. The 13 who are based in South Africa, do administrative work, including finances and logistics.

The first 13 farmers - known as the voorspan or advance team - arrived in the village of Malolo just before Christmas last year.

At first they cleared 1200ha for maize. They worked around the clock in shifts and within a few months they produced a "beautiful" crop and sold it to the government for R2400 a ton. The neighbouring American farmers sell their maize for R3000 a ton.

"The Americans next door got 20000ha in 1999 and they only managed to clear 300ha and plant on it," said De Jager.

In addition, the South Africans planted 80ha of soya.

They have also improved residents' lives. By fixing old pipes and pumps they gave the locals access to tap water for the first time, and they employ 200 people on the farm. The local baker no longer sells bread slices - he sells 200 loaves every day and has employed the local chief, his wife and son.

"The cost of electricity is much lower than in South Africa. Also, there are no trade unions on the farms so you don't have strikes the moment harvest time begins," said De Jager.

Farmers, including Neil Karg, whose wife and housekeeper were murdered on his dairy farm in KwaZulu-Natal in 2010, and former Angolan prisoner-of-war Wynand du Toit, joined the community in the Congo.

Pieter Mulder, Deputy Minister of Agriculture, Forestry and Fisheries and Freedom Front Plus leader, said South African farmers are being forced to leave this country because they face an uncertain future.

"Maybe the two or three years listening to Mr [Julius] Malema wasn't a positive contribution either," said Mulder.

Now, he said, there is a government that "appreciates us".

Mulder visited the Congo earlier this month and said President Denis Sassou Nguesso and Agriculture Minister Rigobert Mabondou were impressed with the South Africans. He said their success is a "bitter-sweet" story because South Africa has lost valuable expertise.