How long does a sim swap take?

I just got the new iphone 5s and I had to get a new sim to fit it as my old one was standard size and I needed a nano one. I wanted to keep the same number so phoned T-Mobile customer services to do a sim swap and they said it would be active straight away but my new phone still has no service. My old phone with the old sim works and has service but my new phone the one I want to move te number to has a sim in I but no service I can't call or text on it. So normally on T-Mobile how long does a sim swap usually take?

I think you should deactivate the previous one to activiate the new one If I'm right and understood! Two phones with one number?!

T mobile and orange say it can take upto 24hrs before your old sim de-activates and when that does your new one activates its how it always was with me with orange