Complaint about shocking penalty of Telkom Internet

Hello. I'd like to complain about Telkom internet. I contracted TelKom internet on November 2016. I have been using at the moment for 3 years on November 2019. I app**** for cancellation of internet last 30 October due to leaving to my home country. I've received the invoice email today and I was so shocked. I don't know the reason exactly about the penalty. The penalty charged is R2260.49. I suppose the reason of penalty roughly below. I received a new router last month. At that time I didn't know why Telkom had sent me a new router. I couldn't see any detailed notification about new router. I didn't apply for the new router. So, I installed the new router because Telkom offered me the new router freely. If the installation of new router meant a renewed contract, I had never used it. Telkom didn't notify me about new or renewed contract in advance. Therefore, I can't accept the penalty charged me. I'm so regretful because Telkom did commit a ***** to me. Please let me know in detail about why Telkom charged the penalty. I would like to demand to waive the penalty charged me.

My Telkom *** / Invoice no: A*** / Name: Mr Seongmo Kang