Airtel — Poor Service on DND

I have Activated the DND Service on 12th Decemeber 2020 and I have received text SMS that DND service is activated.

But Still after that Promotional Calls and Service is coming everyday.
When I Called Airtel Customer Care, they said It will take 10 days to activate the service completely.
I waited for 10 days but after that there is no Solution for my problem, Everyday I am getting Spam Calls.

Since 22nd Dec till today, I called 10 times In customer service and every time they say From now onwards it will be stopped but still I am getting so many spam calls everyday.
This is really Disappointing and very bad service by you.

When I registered for Complaint they have given me a Complaint number and after 2 days they said issue is resolved even after that I am getting spam calls.

This is really very bad, I have already spent my time on your service- 10+ Calls.