Random numbers keep calling me saying I am bein sued should I take them serious

I can't say about your particular case, but we have had many clients receive harassing, clearly illegal collection calls from collectors trying to collect very old debts, usually old payday loans. The collectors threaten them with criminal prosecution and different crazy things, like the sheriff is on the way to your house to serve you with papers right this minute. I'm not saying what could be happening in your case, but in the cases that we have had like this, it has turned out to be scam. Nothing ever happens, no one is arrested and no one ever gets served. You may want to try "Googling" the phone number. When I have done that I have often found many other people who were harassed from the same phone numbers. I suspect that these "renegade collectors" are behaving illegally like this to make some quick cash and because they are either judgment-proof and it is impossible to collect a judgment against them, or perhaps they are outside of the U.S. But you can always file a complaint with the Federal Trade Commission, the Consumer Financial Protection Bureau, and/or your state's Attorney General.