Stalked & Harassed by by Shapiro Shaik Defries & Associates

I have been receiving numerous calls from this Shapiro Shaik Defries & Associates despite me settling my account with one of my creditors. Whenever they call me they remain silent on the call and then hang up. I assume that every time they call me they billed me for it as they were previously doing. I have advised them via email to stop this harassment and stalking. However they ignore me. I have also asked for management to contact me but nobody does.