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* Each number can be auto- or manually renewed. So, they are NOT disposable one-time numbers.
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Do you happen to know whether these numbers are unique? Or do they just wipe the history of the text messages and give it to somebody else whenever you stop paying for your subscriptions?
I do not know, of course. If you need certainty, you need to go a normal physical SIM route and pay monthly for a plan, of course. In any way, we all need to assume that all those bitcoin-paid services may disappear at any time.