Hacks is a serious matter, and you can't just accuse someone off of one rdm.
one rdm, yeah, okay, a coincidence
two rdm's, now you're pushing your luck.
three/four rdm's, yeah, ghosting or hacking
To see whether they are ghosting or not, try ot see if anyone who was a fellow T is on their friends list. Though this isn't always true, it's most likely.
If it's blocked, pretty sure ghosting.
Hacks, usually they make it obvious.
with either, you need atleast 3SS's to prove something. But with this you only have a coincidence.