Living in flimsy shelters made of wood and plastic tarp or half-finished concrete buildings, South Sudanese who have returned to Sudan are finding life tougher as their former country's economy tumbles.

"It's very difficult. Life is worse than before. We can't figure out what to do, neither here nor in the South," said Toka Ayman Agok, a mother of nine children.

After decades of conflict, South Sudan gained independence from Sudan in 2011, and hundreds of thousands of people moved to their new country.

But years of civil war and deepening poverty have followed, and many South Sudanese have now moved back, while some were never able to make the journey to begin with.? ?

There are more than 800,000 South Sudanese refugees in Sudan, according to the U.N. refugee agency, and about 113,000 live in makeshift dwellings in and around the capital, Khartoum.

They are no longer citizens in Sudan, and struggle to get access to education and healthcare in their former country.

"I got sick and my life in the South became difficult, I couldn't find any treatment or hospitals so I came back to Khartoum," said Alissa Deng, who said at first she was able to work as a house cleaner, enrol her children in school, and rent a home.

But Sudan's own economy has stagnated, with an economic crisis deepening since the military seized full power in October. There is triple-digit inflation and rising hunger.

"My landlord raised the rent to 50,000 Sudanese pounds and kicked me out ... I took my kids out of school," said Deng.

Illness has stopped the widow and mother of five from working, and with little source of income she was forced to move in with relatives on an abandoned plot of land in the city of Bahri, which adjoins Khartoum.

Rights groups have long advocated that South Sudanese have their rights as Sudanese citizens restored. Attempts to improve their lot have stalled, while most depend on aid groups for cash or food as well as help accessing education.