you already know tm many years back absorbed the debt team from packet one (p1) that infamous for blacklist CTOS defaulted customers

tm has credit limit system of about 2 months billing if no more. (pls ignore the rm500 limit, that actually just one of criteria. just like car warranty, "whichever comes first" also applies here

if tm suspend your unifi after 2 months default, you need to pay up those two months outstanding plus some small reconnection fee (fortunately unlike assterok, no need renew contract)

however if ignore such and left suspended for longer, the outstanding is gonna to be snowballing into huge amount and tm will blacklist/CTOS you eventually as well as some legal action like hiring lawyers for debt collection

just my 2 cents