SPREADING MY PRIVATE NUM WITH FALSE DESCRIPTION

Good day. I'm new at this but I really hope I could get some help. Thank you in advance.

Late February this year or early March I started receiving texts from strangers and they kept telling me they got my number from Facebook. The first batch of them were asking for a 'sex' mate. I was angry but tried to talk to one of them who apologized after learning I wasn't that type. I asked that person how and where he got my number. He gave me two fb pages and a name of John Garcia (which I assume to be a fake name) who was supposedly the one spreading my number and saying I'm looking for sex. It got quiet for awhile but then messages still kept pouring in. Fortunately, I have a "Block numbers" application in my phone and tried to ignore them but there were also calls which I can't ignore. Some also tried to message me in facebook including that John Garcia but I blocked them all.

Is this harassment?

I had this number for a long time and I would change it but I'm still currently looking for a job and i had that number in my resume. Changing it now would reduce my chances of employment.

How do I stop them when all I have are numbers and  fake name?

few options.
1. ignore mo na lang mga messages,, just delete them when received. they will eventually stop.
2. Access the status of your employment hunting, if still can change ur number, u can change now.
3. change number once hired.
4. if you want to catch the culprit,, u plan for an entrapment, bait him, of course u need some help here...