OnSIP is designed with an open architecture that is compatible with any SIP phone, designed to add flexibility to any calling plan, and easy to set up. It’s almost as easy to quit OnSIP as it is to start.
First, a reminder about OnSIP’s starting policy. You do not even need a credit card, there are no long term contracts, and OnSIP does not sell phones directly. That may be the biggest hitch when it comes to cancelling OnSIP. You are on your own when it comes to returning your phones, and many online retailers do not make it easy to return phones. To cancel your service with OnSIP, log in to the administrative panel and contact support via email. Email the team that you wish to discontinue your service.
You must mention in your email any phone numbers that you have ported, or expect to port out to another provider. There is a specific tab under the administrative portal that deals with telephone numbers. It is, as they put it on their web site, “important that [OnSIP is] made aware of this information to prevent an in-use number from being redistributed to a new customer.” In other words, if you do not ask them to hold on to your number they will release it to the pool of numbers to be distributed to a new OnSIP subscriber. An OnSIP administrator has to complete the final step of removing your number from the database when you port your number to a new provider. As with all number porting, be sure that the new and old phone companies are on the same page when it comes to porting your number, and be sure to follow up.
Once your account is closed, you will permanently lose all your phone numbers, all your data including voicemail messages, and you will lose all settings, such as routing rules. In the event that you decide to go back to OnSIP, none of these settings, numbers, or voicemails will be restored. OnSIP gives SIP credentials away to anyone for free, so, presumably, those credentials are not deleted. If you continue to use these credentials, you’ll have to use SIPdroid, BRIA, or another SIP client.