Blaming the OBi device for that is way off base. It doesn't matter how many volts you send into the ringer, if the bells are spaced too far apart, or the capacitor is shot, it's not going to ring. You will have to fiddle with the bell adjustment to get them close enough for the hammer to hit them firmly. The bells are held in place by screws in the center. You can loosen the screws slightly, then rotate the bell to move it in or out (the fastening is elliptical).
IF the OBiTALK portal was working properly (and it is totally broken at the moment), I'd tell you to sign into your portal dashboard, get into Expert configuration mode. But, that's not going to work.
So: pick up the phone and key in ***1 and listen to it speak your device's IP address. Open a web browser to that address. The default login is admin/admin.
Go to System Management-->Auto provisioning-->OBiTALK provisioning, un-check the blue box to the right of "Method", then change the method to "Disabled". Scroll down, tap the Submit button, then reboot the device. After it finishes rebooting, go to Physical Interfaces-->Phone 1 Port. Find Ringer-->Ring Voltage. Un-check the blue box to the right, then change the value to 82 volts. Again, tap Submit, reboot and wait. Now try calling the phone number. Does the phone ring? If not, you can't make it work.