Porting question - Cell C

Hi Cell C Rep

I am planning to port my MTN number to Cell C shortly. Please can you advise me on the order of events:

On your website you can submit a number and select when your contract is terminating, if my last day is 17th of September which do I select? As options are 0 or 1-3 months

What are the terms and conditions of porting away should I not get adequate service via Cell C ?

Lastly do I port first then give notice on existing contract?

Thanks