Now I can't say for 100%, but the answer I'll provide is most likely the case with reliable sources
So I've done some searching around the forums, and the answer is:
Yes, tp trapping/killing is allowed in factions
If we think of it, Scamming is allowed in factions, and tp trapping/killing is just similar to it (Deceiving and taking advantages).
Sources I've looked into:
1. Rules, it's not written anywhere in faction's rules, meanwhile it existed on Skyblock's rules. (But the rules might miss some changes right?)
2. Threads. There are several though old (1-2 years, latest one is on April 2020) threads which experienced players or staff clearly stated that tp trap/kill is allowed. This is pretty reliable, and considering that it's not added into the rules, this should still apply until now.
The last thing I wanted to say is that I haven't asked others in discord (For some reason I can't open discord rn)for more confirmation, but regarding that staffs and donators said no before, it could be either your question isn't complete, they thought you were talking about Skyblock, or they prob didn't knew about that. (Donators and experienced players are not always the same, staffs are very reliable source too but they are also human).
Or, the rules actually changed and a part of community didn't knew about that and it's not updated on rules, but this is unlikely to happen.
So, that's my short analysis about what is happening regarding to your issue, once again it's not 100% accurate but the answer I gave is most likely to be true. You can ask or wait a clarification from staffs member or experienced players about this, if you still have any doubts. Hope this helps and have a nice day!
Oh, and quick link to 2 of the threads:
I tp trap on other servers and was wondering if it's ok to do on jartex factions?
jartexnetwork.com
When buying a rank in factions , you will have the ability to break spawners, which soon people will ask you for tpa to them so you can “break their spawner” - which is mostly a trap that will trick you and which also is very affective towards people with rank Welcome to factions reality
jartexnetwork.com