Probably due to it once being used as spam from another customer. Your phone number will go back into the pool to be used again kinda like an IP address. I love how the first response to your question was answered. Alot of forums are like that nowadays. And watch this now get closed. ;)
I am here to answer any technical question related to app development on RingCentral platform. As you can see from other questions/answers in the Forum.
I cannot answer your question not just because it is not a technical question but also it is not in my knowledges.
You can also post such a question in the User community too if you don't want to submit a customer support request.
And one last thing. No, nothing get closed in this forum. This is not a dedicated support channel so all questions which can be answered will get some kind of answer and is open for further comments or additional answers.