Sangat who mention being troubled by such things, listen to Sukhmani Sahib, keep it on in the background while working/doing housework.
If it’s really troubling you, then listen to 1 paath of Chandi di vaar. Just 1 paath per day, it’s too powerful to do more. Do it at amritvela, keep a glass of water and sprinkle it around your house after (remaining water drink it). Once the problem stops (it will stop fast) stop Chandi di vaar completely (really is too powerful to keep doing). But then do Sukhmani Sahib daily and such things won’t return.
Black magic is very real. People meditate on the heart chakar to obtain power then misuse it to harm others. (By meditation I don’t mean simran). It’s very dangerous they can curse people, make people ill, kill people.
But it won’t work on someone who does (enough) simran/abiyaas. In fact if someone tries such a thing on a gurmukh the Guru destroys them. Just like a disruptive student gets removed from the classroom and sent to the headteacher. Anyone who tries harming a Gurmukh gets removed from their body (they die early, before their time) and get sent to hell.