Green Flag - delayed response

I have Green Flag Mayday Roadside and Recovery Insurance. On arrival at a CL recently I found my caravan's wheel hubs to be too hot to touch. I suspected a malfunction of the brake overrun system and this subsequently proved to be the case. I phoned Green Flag at 5.30 pm and because there apparently was an unusual number of callers waiting, I opted for a call-back. Green flag returned my call at 8.45pm and informed me that they did not deal with brake problems. I was also advised to take the van to a garage from which it could be recovered. This made me wonder just what matters are covered by the assistance package if brakes are not a priority. I was also puzzled - if the problem were to be fixed by a garage why would the van need to be recovered? I've towed  thousands of miles confident that I had an insurance "umbrella" for times of need, perhaps that umbrella has a few leaks?