Extremely disappointed in VODACOM'S BAD SERVICE

I have 2 contracts with Voda om and service I get is beyond bad. I have been referred to a sub. On 30 August I spoke to Teandre(not sure if spelling is correct) regarding laptop and router contract which shows 24 months which I agreed to on 20 April 2018, she was very arrogant, apparently she could not find my details on the database. All of a sudden it has been changed to 36 months. They all say laptops are 36months,i should've smelled that I guess, but the agreement was 24 months. I spoke to Venchenza and all he sees is 24 months. The other contract was renewed last month the lady promised me a deal of R279, the bill came to R518. Again Vodacom stands out of the water and referred me to a 'sub'. All I know is I pay Vodacom every month (their banking details didn't change, the same with the network :Voda om) I have been sent from pillar to post. VODACOM I'M DISAPPOINTED