It can be due to different reasons:
- "Block Top Spammers" wasn't enabled within Truecallers > menu > settings > Block.
- The number is newly marked as spam and therefore not yet put into the official top spam list.
- If you're using any battery-saving apps kindly disable Truecaller from that list as Truecaller needs to be running in the background in order to block calls.
Note that some spam calls with lower spam reports may not be blocked as they are not considered top spammers, yet. We do our best by warning you in those particular cases. In addition, we have a Premium feature named "Block extended spammers" which should block and capture more spam calls.
Feel free to contact our email@example.com and share the spam number so we can investigate further.