Facebook carefully guards users from spam and annoying commercial mailings. Even after template messages are approved, all business activity related to the use of WABA will be monitored and evaluated. Spam complaints in particular are taken into account. It is also taken into account how active the users' communication with the company is.
In addition to possible blocking of template messages, there is such a control tool as a rating or trust level that is assigned to each number. The number of unique contacts to whom you can send an outgoing message within a day depends on the level. There are three trust levels in total. The 1st level allows sending messages to 1 000 contacts per day, the 2nd - to 10 000, and the 3rd - to 100 000.
Each newly registered number is assigned the 1st level. Further increase of the trust level is automatic. In order to do this, the number of sent notifications must exceed twice the daily limit of outgoing messages within a few days. That is, in order to move from the 1st level to the 2nd one, you need to have 2000 sent notifications. After that, the rating is improved for a few more days.