if it truly is Receivables Performance Management here is their info:

Customer Service/Web
20816 44th Ave. W
Lynnwood, WA 98036

About Your Account
PO Box 768
Bothell, WA  98041
Phone: 1-866-212-7408
Email: account-inquiry@receivablesperformance.com


Payment Dispute/Inquiry
payment-inquiry@receivablesperformance.com
or toll free 1-800-618-6709
fax 425-412-2575

Receivables Performance Management
Attn: Payment Dispute/Inquiry
20816 44th Ave W.
Lynnwood, WA 98036

I called 1-800-618-6709 and someone answered.It was a debt collector looking for the person who had my number before I was lucky enough to have it.They used caller ID to verify that I was the one on  the "call and annoy"  list.They said the calls will stop in 24 hours.
They called me on average 10 times per day before I found your post.I call blocked the following numbers
314-627-5652
240-210-7113
I blocked more but my history of them is gone but these number may be from the source
The following numbers may or may not be the same company.
760-705-8888
360-722-5901
602-625-7068
480-245-5745
I was told they use many numbers to call[harass] from."Gets the system past call blockers"
When I answered I was put on hold.The longest I waited for something to happen was 30 minutes.
These people need to be stopped!I blocked the numbers but still get one annoying ring and these people call late at night and early morning.
Thank You Kim for the number

314-627-5652 Per R on the caller ID, Linked to RPM debt collectors.

Installed a Fax to my attacked-office-number, and added their number to the spam list; that made them stop calling me for a day.

disconnt/busy signal when called/answered

no person on the line, no messages left, just call and hang up.