@Stacey Tucker Good news! I found a solution for you. Please give this a try.
Accounts can have Virtual Extensions/MVP Free extensions that are good for a few things, one of them being access to the account without a license. (Third party IT access, reports login, summer intern, etc.)
To add a virtual extension: service.ringcentral.com > Users > Unassigned Extensions > Add Unassigned Extension > Domestic > Add users Without Devices > Make appropriate selections and be sure to select "No" under "With Numbers".
The process will have been done correctly if it reflects $0.00 upon completion. (There will only be a charge for this type of extension if the user uses it like a phone line. If it is used like a phone line 10 times in a month, it will be billed as a full license for that month.) The virtual "user" should be able to use their credentials to log into RCU.