Possible to factory reset an Obi1022 that has an admin password?

[malcolm@malcolm.cc]

I have an Obi1022 and it works great.
I recently bought a used Obi1022 on ebay. It arrived but I haven't been able to connect it to my ObiTalk account.
It powers up, but it has an odd screen programmed into it. It appears it was used for a service called Go Deskphone ( https://www.desk-phone.com/go/ ).
- I tried to add it to my ObiTalk account using **5 and a 4-digit code provided by the obitalk web site, but it doesn't connect.
- I tried to type ***8 but as soon as I get to **8, I get a three-pitch error tone.
- I tried dialing **9 222-222-222, but as soon as I get to **9, I get a three-pitch error tone.
- I did a factory reset on it using the instructions at https://www.obitalk.com/info/faq/obi-ip-phone/phn-factory-reset but it still comes up with the "go/deskphone" screen.
I found an "factory reset" option in the settings menu, but when I select it, the screen reads "Enter Admin Password"

Question: Now that I own the phone, is there a method to reset it in such a way that I can remove the "go/deskphone" programming and take control of it?

[RFC3261]

Question: Now that I own the phone

You may have the phone in your possession, but it is possible you do not have title to it.  Some providers provide low cost/free devices to their customers as part of a long term contract (you essentially are paying for the device over time).  This is no different than some mobile/cell phones.  The person who sold you the phone (presuming they had been given clear title to the phone) should have had Go Desktop unlock the phone before selling it.  It is also possible the person selling you the phone did not have clear title (or still owed money on the device).

is there a method to reset it in such a way that I can remove the "go/deskphone" programming and take control of it?

You can attempt to contact Go Deskphone and request an unlock code.  From the unit address they should know who their customer was and whether there is any outstanding balances.  Or contact the person who sold you the phone and have them do so.  Or return the phone to the buyer as unusable.