Yes. A pact is for a long-term working, and is not recommended for either a one-off curse, or until you have built a relationship with the entity.
This is not an issue. if your visualization is good you don’t need entities to do this anyway. There IS an issue in that “like attracts like”, and if you fling poo, you attract poo to you. …there’s also a phenomenon called back firing or “backlash” that can happen when you try to affect other humans and their protections are better than your will to affect them - you’re starting a fight and you may not always be able to finish what you started. Get your protections and spiritual hygiene in place before you start, know how to get rid of unfriendly entities that want to feed on your negative energy before you start. You are your thoughts, control your thoughts.
Here is a getting started guide - for this forum and magick, both.
You’ll want to get your spiritual hygiene sorted out, and start work on developing your astral senses.
Then when you can know you have a decent chance at avoiding impostors and parasites then try the first contact guides we have on here.
For reference:
The rules are here
The posting guidelines are here in the FAQ