internal messaging with contact form

hey
currently i am trying to set up a website where user can create a listing and other users can book this users listing. for this issue i created a contact form on the listings page with contact form 7. users can now contact the listing owner.

the problem is contact form 7 only sends an email to the listing owner.

what i want is to have all the required conversations between the users on the website.

What i need is something like a internal messaging plugin which can be linked to the contact form 7 plugin.

i tried plugins like front end PM or cartpauj but they were not the perfect solution.

looking forward to hearing from you
Niklas