Router Collection

I am so frustrated with Rain. I cancelled my subscription with them on the 15th April 2022 and the Router was collected with no hassles, now all of a sudden I am receiving calls for collection of the Router. The person they are looking for on the phone is not me and even the address they want to collect from is not mine. Now I am even getting e-mails for collection. Can they please update their system accordingly because this really frustrates me. I will be taking this up with my legal.