So far during their stay at this hotel, that couple have done nothing but complain.
A) Throughout their time at this hotel that couple have had no complaints.
B) Up until now, that couple haven't had anything to complain about this hotel.
C) All that couple have done since they arrived at this hotel is complain.
D) They've only made a couple of complaints about this hotel so far.
E) Since they got to this hoteli nothing has caused that couple to complain.