For everyones safety i suggest that you "Promote" the usage of WhatsApp on the site when advertisers create and ad. Maybe add text "For everyones safety we and clients prefer usage of WhatsApp! Not FORCE it but rather inform and recommend!
My suggestion is to add it in the beginning "PERSONLIG INFO & BIO" Or more appropriate in "KONTAKTUPPGIFTER"
Its best for everyones safety. Since call and messages are encrypted. It benefits everyone! We all want to meet discreetly!
Also should force the site to ALWAYS use HTTPS. This does not always happen! Now its browsable without SSL. Its not even default for me!
Awaiting feedback! :)
Thanks in advance!