http://www.businessinsider.com/ recently published an article on corruption in Africa.
I don't have the other side of the story but this is a very common tale which is certainly not unique to Senegal. Few, if any, of these large licenses or concessions occur without corruption. I am not saying this happened in Millicom's case and I certainly have no inside information but a lot of times these stories become a scandal only when "corruptor" and "corrupted" stop seeing eye to eye.
I read comments that Millicom's license had been revoked for number of years ago but they were still able to do business. Under what agreement? Why didn't Millicom protest then? I am not in any way defending the government of Senegal but in the game of corruption, it takes two to play....
This should serve as an example to other companies who tend to close their eyes when they first want to get in and then are surprised when their former partners come begging for more. I remember meeting a delegation of one of the largest US telecom companies coming to the country I am in. They were really interested in the market. They eventually decided that the risk was not worth it. As they explained to me in private, they were not "experienced" enough with the business environment.
African nations should understand that by requiring foreign investors to bribe officials to get these licenses and concessions, they will get a type of investor that is not necessarily a good corporate citizen. Real investors shy away and sharks come in to do business.