Who called from the number +1 (951) 525-6868

Left a robo call message that was partially cut off and I thought a collection agency had me mixed up with someone else. I returned the call and a man said he was an IRS Agent and I owed back federal taxes. I said I didn’t and to mail me a certified letter. He said he already sent one to my address and rattled off my correct address and I told him he was a liar and hung up. This call took place on a Saturday at 6:30 am— hardly IRS day or time of business! Additionally, I received another message from this same # 951-525-6869 at 11:30 am—then I remembered to block this scammer’s phone number! I have seen online he also has claimed to be law enforcement when making calls to others! I am far from the first or one of the few to receive a call(s) from this number by looking at other sites! Beware!