I am sure that is your experience, and this would likely not be an issue with a business account, where the SIM's and numbers are managed under a single account. In my case this is a consumer data plan, prepaid SIM which are individually managed with dedicated payment portals for each number. In this case each SIM is managed under an individual account, and can not be bulk administered. This is how Verizon and AT&T on the consumer side of the organization do it. When you setup your account to manage the SIM, make payments and reload data, the system sends a PIN code to the DID for the SIM. I will add that it occurred to me after posting this question that being able to send message to an MG using SMS could be turned into an interesting feature, like having it reply back with status messages, very much like sending messages to via an API. Its could provide another interface to developers.
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