Owner of our condo we rent to refuses to give up a copy of the property registration and ID card

Hi,
I meet the requirements to obtain a marriage visa and have gathered all the documents that I need apart from the owner documents. However, my life companion and I rent a condo which we have been renting for 2 years. We have asked the ownerto give us a copy of the property registration and her ID card. We told her we need it for a visa at immigration. Now, she doesnt respond to our phone calls and messages to her our unanswered.
We went to the juristic office and spoke to the manager, The manager said she cant give us that information without the owners permission. Which is understandable. However, when we asked the manager to call her she refused to call the owner on our behalf.
After spending time to gather all the documents we cannot provide further because of this. The only alternative is to use my life companions brothers house who are ok to give usa copy of their documents. However, as we dont live there I dont want to put that address down.
We have always paid our rent on time and have never had any issues with her. I guess she is worried about giving us a copy of those documents as they are personal.
Any advice on how I can proceed with a case like this?