bKash subscription charged after clicking Truecaller ad

A notification pops up on the Truecaller app saying it's offering free MB. I click on it normally. Then I register with my bKash number. After doing so, I didn't realize that something like this would happen.As soon as the money arrives in my bKash account, 60 taka is deducted. Which is not a lot, but now I don't understand how to turn it off? It was a bKash subscription. Which I activated by mistake. So be careful. Don't click on any such ad by mistake. Don't login or register in any way. It's a spam.