Swiss nationals - help wanted regarding Voluntary Swiss Social Insurance (AHV/AVS)

Dear all

Does anyone have any experience how to be able to pay into the Voluntary Swiss Social Insurance Scheme while living in the EU?
I have not been working for the last year, have been traveling and studying but with my base in London. My application has just been denied... because I'm living in the EU..

Any suggestions what would be best or alternative solutions?

Thanks for your help!
Lisa