I have cancelled my cable service within the last few months and have been getting calls from this company up to 5 times per day at first.  I never answer the calls, so they have dwindled down to 1 time per day usually.  

My caller ID shows the calls with different displays.  Sometimes it will say ESM and the phone number, other times it will show up with just two numbers and no identification as to the company name.

Very aggrivating, needless to say.