I hope you have read and understood the contract you signed for?
This contract contains regulations about availability - and it states that there's only 97.5% availability over the year - so 9 days of outage per year are within the contractual limit. So demanding any kind of early termination by the end of next week is complete nonsense.
You first need to raise a complaint and inform Vodafone about the problems - this has to be done through the Hotline and/or the ticket system -- and after that, Vodafone will check the issue. There is no right for any kind of premature cancellation without even informing the other party about the issue and/or raising a complaint - the other party must have the chance to solve the issue.
And by the way: Even if your cancellation would be accepted - you wouldn't get a new line within one week. DSL lines usually take 3..6 weeks for the initial set up. So in your case the cancellation would (in theory) lead to an extended period of at least 2..5 weeks without any kind of internet connection at all... But this just as a sidenote as your cancellation request is completely void.
