I think you should rather talk about options to make the client happy. Even if it might cost you something (something you have or something you have to purchase)
You states
"they're not willing to accept any other offered solution. ". I don't know what you mean by this because up until now you have not provided any form of solution. The only thing you stated was wait till 10th. So saying I am offering you the solution to wait till the 10th and if you not willing to do that then I am going to force you to take
"the easy way" in the form of cancellation is a bit odd.
I have in all of this not rooted for any bad behavior. I am the last person enjoying the fact that people are having a go at you and Afrihost. I have however throughout this public conversation rooted for Afrihost to come to the table with a solution that will benefit the client, as you have not been able to provide the correct service due to Telkoms slacking and/or financial commitments. The client hasn't stopped paying. Therefor you cannot get upset if the client is not willing to give you the benefit of the doubt. It has been several months now so I can understand if people arent willing to do that anymore. You should give the client the benefit of the doubt.
Like I said before, I trust you will make the right decision in the end because I have always believe Afrihost is on the right track in terms of Internet in South Africa. In my opinion up until recently you have blown all other ISP's out of the water. Give me a reason to keep believing that.