Telcel information

When we put money on our phone or banda ancha we immediately get a text message (SMS) telling us when that payment will expire. But I have no idea what the rules are. We put $200 pesos on the phone our first chance when we cross. If we use that we buy more. If we don't use it we can check with Telcel on the phone - I think it is *333# and you get a text telling you what you have. We just bought 200p and the SMS said we are good to April 6 I think - so appears to be 2 months. Not sure if it is different for different amounts - we always get 200p. Going north the phone is inactive and when we return we may get a new number if our old number has been given to someone else - but if not assigned they can give us the same number. None of this is a problem for us as we don't use the phone that much and almost no one knows our number so we don't miss calls since no one calls us. If we want someone to have our new number we email them. I know this does not answer the question but if Telcel does not know then maybe no one knows. Every time we buy time we get a regalo of more time - but it changes every time - and the time limit may change also. We have long since given up trying to figure Telcel out as it seems a hopeless pursuit.