Anyone know whos number this is 866-988-1001

They said they were West Management, but only after I asked them directly? They had called my mother and said that they were process servers working with the police department looking for me to issue a summons and asked if she was going to be home. She said I did not live there and they asked her for some of my personal info which she would not give. She called me, I called them and told them I saw it on my caller id and wanted to know who they were and what they wanted? He immediately said that the number would not have come up on caller id and he asked for a case #, which I had but did not give. If they know my name then they should know my address shouldnt they and how in the heck did they get my mothers phone when she lives 90 miles away and does not have the same last name as I do? I cant find any information on this company name as stated nor can I find any information on that phone number. Is this really a process server or a collection agency trying to collect a debt using a fake name and why cant I find any information on this phone number either? Oh and not to mention after I hung up the phone I immediately received a call from a number in Riverside California which I cannot get any information on either..951-286-4452, when I did not answer the phone they called back again which I did not answer again either. Is this really a process server or just someone trying to collect a debt using these types of practices.