BAD BUSINESS PRACTICE AND SERVICE

I joined Mweb December 2020 the agreed packages was 629.00 pm I was told that I had to stay with them for 12 months January they increased the price to 639.00 pm this reflected on the invoice with no prior warning.. when questioned Yumna the sales person advised that she was unaware of the increase after going back and forth and lodging a complaint I was told that it is in the contract and they can change prices, At 10.00 no problem I can live with that, I ask for a copy of the contract,i am told they dont have a contract, then March comes along I receive an email advising and increase to 689.00 from 1 April . I contact them immediately they blame Vumatel as per the email, I contacted Vumatel who advised they did not increase the price only the speed and have an email from them confirming this, Since then I cannot get anyone at Mweb to take responsibility email sent to complaints came back with a vague response . The contract which I agreed to at 629.00 was cancelled as per their system and new one was raised at 639.00 and now another one is raised at 689.00 surely this is ******* I have email both Yumna and her manager Stephanie with Yumna ducking and diving and being completly ignored by Stephanie. Surely this is ******* I request a full investigation. I am entitled to pay the amount as agreed 629.00 not a cent more