"We heard about brutality, about people being killed, people being wounded and their belongings being looted by those who were expelling them," Congolese government spokesman Lambert Mende told RFI.
"Of course we are not happy with this move," he says, highlighting that a joint mission of enquiry has been set up with Angola to ensure that "those responsible for these killings must answer.”
Since 1 October, Angolan authorities have waged a nationwide crackdown on illicit diamond mining, as part of the government's attemps to clean up the illegal diamond mining sector. Last week, four people were killed and several others injured in the diamond-rich Lunda Norte province bordering the Democratic Republic of Congo.
Angolan security forces deny using excessive force.
While some reports claim that 200,000 Congolese were expelled, Mende insists the real figure was no more than 40,000.
"One hundred and sixty thousand came back voluntarily. We are having problems with our neighbors regarding the remaining 30-40,000. Those were expelled with brutality and that is the problem we are concerned with," he said.
The returns come after an ultimatum expired on Monday 15 October for Congolese migrants working in the informal mining sector in the northeast of the country to leave, but came with little warning.
"We have an agreement with Angola that whoever among the two countries has to expel irregular migrants should inform the other country, so that it can prepare to welcome its citizens. This was not made for these 40,000 Congolese expelled from Angola," Mende says.
Refugees among those expelled
The lack of warning has left Congolese authorities with little time to cope with the influx of migrants, especially those returning to places like Kasai, a region which saw widespread violence last year and in 2016 involving armed groups and government forces.
It was this same violence that caused many of the migrants to flee to Angola's Lunda Norte province to begin with. The need to resettle them now threatens to further destabilize Kasai.
"There are so many people and no temporary shelters or food for them," says Crispin Mfamba, a priest in the border town of Kamako, who is dealing with the returnees.
"They are housed in churches and schools, some even sleep under the stars, and fall sick. The humanitarian situation is dire," he told RFI.
What is also disturbing are reports that some of the migrants forced to return, are in fact refugees.
"We are aware of 50 individuals who were apparently registered as refugees, but who were caught up in this movement and are now back in DRC,” Philippa Candler, the UN refugee agency's representative in Angola, told RFI.
"We’re hearing reports that there are people among the 200,000 who are stranded on their way back to places of origin and of course this raises a number of concerns for all of our colleagues on the other side of the border," she said.
Foremost of which is money and how to accomodate them all.
Waiting for assistance
Government spokesman Lambert Mende insists that a humanitarian fund run by Congo's ministry of social affairs has been activated, and that the ministry is "busy working with the four governors of provinces where our compatriots were expelled and each province will send its needs and the ministry will allocate its funds."
Kasai, Chicapa, Kulugungu and Lualaba are the provinces likely to receive the funds, but how much, the government declined to comment.
"This is not something we have to put in the public space, I'm sorry."
Elsewhere, Crispin Mfamba, who works with the returnees, was more forthcoming.
"The regional governor [of Kasai] has given us 4 million CFA francs, roughly 2,500 dollars, but what good will that do?" he asks.
"With the money, we’ve bought bags of flour, rice and vegetable oil, and given it to those most in need; but it’s like a drop in the ocean. The governor has promised there will be more assistance, but so far we haven’t received it.”
According to Reuters news agency, 200,000 people have crossed into Kasai region from Angola in the first 12 days of October. It's unclear whether this figure could rise.
"We don't have a grasp on the number of irregular migrants who may be caught up in this order to leave the country," explains Philippa Candler, the UN refugee agency's representative in Angola.
"The Angolan authorities themselves told us that they had not anticipated such large numbers would be returning," she said.
Impact on elections
The scale of the numbers returning to DRC may have taken Angola by surprise, and it could also upset Congo's upcoming elections.
With less than two months to go before the highly anticipated December poll, security sources are warning there could be potential violence, and with a growing refugee crisis now to deal with, and a diplomatic rift with Angola, Congo's transition to democracy looks to be anything but smooth.