Robot ****s after registering with Openserve for fibre installation

Earlier this week, Openserve subcontractors installed fibre at my home. One must provide a cell phone number for Openserve to send a security PIN as part of the installation process. Within an hour of validation I started being bombarded with Robot **** calls, which I have never had. Somewhere in the Openserve food chain, cell numbers are being harvested. Examples ***, ***, ***, ***.