On-Dot Couriers & Cargo — fraud calls from on-dot couriers, to all my relatives by asking my details to my relatives

I got a call from on-dot couriers. There was a lady who says to me, you have a courier, please share your information. When i asked what is the courier or where the courier comes from. She says we can't share information. I said cancel that courier i don't want that courier. After 1 hour, they keep calling my relatives and asking about my brother's contact number and my home address.
When my relatives informed about this. I was totally angry with the on-dot courier service. I don't understand, where they get my relative's number. They are doing totally wrong, by asking my details to my relatives. I said to cancel the couriers and they keep calling my family member. Please if anyone who belongs to on-dot courier service, please look into it.