Need Advice on what to do with my current company.

Problem/Goal: Need advice about my current employer

Context: Hi, I am currently under a construction company and regular employee ako dito.

Now the thing is mayroon kaming client before and one of their managers was able to acknowledge my potential skills, so at that time na nag t-trabaho kami for their project nakakapag pa mentor ako sa kanya and my skills and knowledge really grew significantly.

And then recently itong si manager ng client namin he gave me an offer to be part of his team. So syempre a-accept ko yun kasi dun talaga may potential ang career growth ko.

Until recently, hindi ko alam kung sinong nag sumbong sa HR manager ng current company ko, pero biglang nag reach out sakin at nagagalit kung bakit ako nag apply sa company na naging client before, she mentioned something that it may be against code of ethics or conflict of interest and told me that they will send a letter to the HR of our client's company and nasa labor code ba talaga yun? kasi sa contract ko wala namang naka state na bawal din to gawin.

Then throughout this conversation with our HR Manager may na mention pa siya na ituloy ko na daw yung resignation ko kasi disrespectful daw na nag apply ako sa ibang company habang kina-kailangan pa ako ng team namin.

Sanay naman na ako sa ganitong instances, my biggest worry lang is may power ba talaga sila mag send ng letter sa HR ng client namin (na a-apply'an ko ng new work)

That's my biggest worry kasi that they may take away the big opportunity I have and anong dapat kong maging action?

I don't have any previous attempts yet kasi I'm being careful of my actions pa at natatakot ako na masayang yung opportunity ko.

Salamat po sa mga sasagot.