First off, we are flattered that you are trying to build add-ons to our software, but this is NOT cool. We are pretty liberal with how people use our service, but DOS-ing people will not only not work as inteneded (we have limits to the amount of calls you can make), it is also against our TOS. Additionally, making a high volume of calls has the potential of pissing off our vendors, which will impact the service for the rest of our users. This is something we will not tolerate, so we are asking you to please stand down. A system like this will cause us to restrict users further, which is something we'd rather not do.
If you are interested in making lots of calls there are other services which are more appropriate for you. Flowroute, Twilio, Airespring, or Telnyx are a few services that will allow you to make these types of calls.