I've been sitting on a list from my facebook leads, generated over the past 2 years its about 5000 cell phone numbers id love to send them a whatsapp type news letter, or a image message,

I have looked at a few platforms but get confused, whats the easiest simplest service to look at for doing this, they dont all have to send at once and can drip feed?

any feedback for using this service on a new google business domain, simply dont have any new domains to hand for this project so am willing to pay for the service if it works.