Am I entitled to a legal action for breaching the agreement of an internship?

I have joined the internship of HR back in last week of September 2021. It was a 90 days internship where I was told over a zoom interview that I will be paid depending on my performance. I attended like 2 to 3 meetings and then I discontinued as I got a full time job offer for which I gave the interview earlier in September. Since then I am being blackmailed by the employer that since I discontinued the internship, I have to pay the full training amount or they can take legal actions. Though In the offer letter they have mentioned that I cant take any job in 90 days or be a part of any other organisation, i have to complete the internship or else if I quit, the employer have rights to demand for a penalty as a training cost(amount will be decided by them). I was a working professional and I lost my job in august and i was searching for a job since then as I need money to pay the bills. In September I got this internship offer and I accepted it because it was better something than nothing. my question is do they really have the right to penalize me with any amount they wish? Can they really take any legal action as they did not pay me anything and I did not utilize any of their resources? They have mentioned that this internship is view as an educational opportunity not as a part time job. the offer letter was full of spelling mistakes and it was clearly edited so should I ignore all of this or take this matter seriously?