Alot of slavery based societies went broke after Britain outlawed slavery. Many African countrues were overdependant on slave labour and slave exports for economic activity and failed to industrialise and modernise. Thats why alot Islamic African countries such as Somalia and Niger, who were once quite prosperous during the 17th century went through severe economic and civil decline during the 20th century. The slave economy failed as the industrial age took off in Europe . Thats the source of so much of Africa economic woes. West African empires especially, as some kingdoms sole exports were slaves to the New World and Islamic caliphates and many kingdoms became so rich that they started waging wars on weaker kingdoms such as the igbo for the sole purpose of capturing slaves. Thats why many African Americans can trace their ancestry to the igbo people of nigeria
Most Igbo were captured and sold by other Igbo from different clans or towns.