Contact form problem on my site

Hi i have a contact form on my that page [ redundant link removed ]/
And I want to work it in that way.
On my website, there is some members registered and each one has a unique 4 digit username.
I want that User can contact with each other through my website using that form.(I mean a user can send an email/message to other users). But the issue is that users know the username of each other not the emails,

So what I want. User A use User B username id in that form email will be picked from the database against that username and will be added as recipients.

Inshort users use their username for contact while system will get their Email from backend and deliver email to them

Please help me in this matter .i will be very thankful to you

• This topic was modified 6 years, 5 months ago by Jan Dembowski.

The page I need help with: [log in to see the link]