Vox Telecom unfair practices

I took a home fibre with Vox in February 2021 and was told that I would not pay an installation fee if I stayed with them for 12 months. Unfortunately due to reasons beyond my control, I had to move to another complex in July 2021. I informed their sales team about this and even asked them to reconnect me at the new premises.The problem now is that I am being charged R2200 for the cancellation at the old unit and another 3 month's usage of R719/month even though I indicated that I am moving premises and I have not used the old line since I moved out on the 30th of June. It was never properly explained to me that I cannot transfer services from one unit to another and also that the cancellation has to be in writing. This now means I must pay an extra amount of R4 300 for a service I am not using on top of the R719 for the service at my new address. Even if I decide to leave Vox I am still liable for an amount of up to R6000 which I think is very unfair and frankly holding consumers to ransom for taking their services.