Fibre tariff drama

Vodacom fibre services is my worst nightmare so my initially package for fibre was R499 per month for the past 3 month my instalment has been changing called their fibre call centre and I was advised that the increase was due the fact that the initially speed that i signed up for was no longer available so they decided to change my package and upgrade me to a higher speed without consulting me.

My question is who’s problem is it that the speed is no longer available and why must it have an effect on me financially and why was I not advised on those changes? who has funds laying around to accommodate your instalment that increases every. All I want is a fixed amount until my contract comes to an end thank you