Dippy, may be a little harsh in this thread, but he's right...it's a feature where weaker opponents can rob stronger opponents. There are least 1,000 threads on this. If this weren't the case the weak would get more and more discouraged and the game would die....
Collecting on time is the only pure defense.
If you think you are frustrated, imagine how those gold spenders who bought dozens of Bodyguard Agencies and wasted the time to level them to 10, only to find out they are near worthless....