How this company get my data and how make call

I purches aqua guard water purify I regularly serives from same company but this December month I received call from call centre one lady told she call from aqua garurd and your fileeter changing time is near so I told come and change I paid 1450 for services on 27.12.17 but today 20.1.2018 aqua guard sevices men come direct at my door step I told him my serives already done by you he told it’s not company person it’s face company and now your machine is out of warntty he told carbon cost 500 and I paid 1450 it’s ok but I want know how fake company get my all data how know my serives time how dare to fake call and come to home to home with name of other companey