It shouldn’t take any time. I have had my T-Mobile account add minutes after I went over and they backdated it to my last bill so it never showed that I had gone over.
When you set things up it takes effect immediately. If you are worried call their customer service and ask for it to be backdated to your last bill. They have no problem doing that. 
Also, go to your online tmobile and check your plan details. It will tell you exactly what your plan is and how many text messages you have used.
well it Vere’s but most of the time it will take effect right away
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It shouldn’t take any time. I have had my T-Mobile account add minutes after I went over and they backdated it to my last bill so it never showed that I had gone over.
When you set things up it takes effect immediately. If you are worried call their customer service and ask for it to be backdated to your last bill. They have no problem doing that.
Also, go to your online tmobile and check your plan details. It will tell you exactly what your plan is and how many text messages you have used.
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I am a t-mobile customer
should be right away there fast
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A matter of minutes.
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it took me like 3 seconds
but mms was diff, you have to "activate" it via mytmobile.com
from there itll let you know what to do, also if you recieve/send a mms youll get a text telling what to do
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