Solving a problem with fake leads(probably from bot).

Hi, I have the following problem. I started to advertise with popup networks a few months ago and it was quite profitable. But last month we started to receive a lot of fake sales from this type of traffic. We are using order form and are calling every customer who make order. Most of the phone numbers are fake, but sometimes the phones are real and the name is the same, but the person says he didn't ordered anything and don't know about the products. We are working with 5-6 different networks and the fake leads come from all of them. We think it's some kind of bot that is filling our form. We tried to use CAPTCHA and HONEYPOT to get rid of it but it didn't worked. Or it may be our competitors doing it. I'm looking for someone who can help us solve this problem ASAP! Thank you.