Not sure if anyone has seen this but it's not listed as a known bug (or I cannot see it)
I purchased 5,500 cartel coins and unlocked level 69, the game took my cartel coins however no levels were unlocked.
Within the ledger on swtor.com, it seems the 100 spent cartel coins for each level.
I have since completed a quest and unlocked another a level, but now I'm out 100 cartel coins...