Before you start your broadcast/blast, there are certain guideline you have to follow in order to minimise the risk of being ban
Do not use a new number. You can't just go and buy new number and start blasting. You will be banned right away
Make sure to start blasting to the latest database first. The ones who are recent contacts and still remember us (hot & warm audience)
Avoid making the delay too short to prevent WhatsApp from thinking it's a robot. Use a delay between 45 to 90 seconds to begin and you can decrease it over time

Don't use a pushy tone in the script when contacting old databases to avoid coming off as spam. Check out this link for more details on the script and types of databases: Click here
To generate two-way communication, you can ask for a response by ending the script with a question (optional)