Ndad texting my coworkers

I (28 F) went no contact with my Nfamily and told them that I was not inclined to speak to them if they are going to be unkind or disrespectful to me in anyway. When I had moved out (6 months ago) I had gotten my own phone plan about a month later (this will make more sense later)

I then get a text out of the blue from one of my coworkers asking me who Mr. Webb (my Ndad) and Curtis (my husband) is. I explain who they are and my co worker sends me a screenshot my my Ndad calling her and demanding if this phone number was my husbands because they need to know where I am as I haven’t spoken to them in months. He had also called her repeatedly hence why she said to text her only. My coworker blocked the number when I told her of the situation and I broke down at home because I am terrified. The text can be seen here

I have absolutely no idea how my Ndad could have gotten my coworkers phone number other than he was tracking who I was calling and texting at the time when I was on their phone plan. I have no idea what to do at this point as I have made it clear I do not want to speak to them, I’m not in a place emotionally to break my N/C to remind them I don’t want to speak them as I know it will give them the power and they want a reaction from me. Any advice is appreciated