This happened to me yesterday:
My small julii army (general unit and 4 units of hastati) was attacked by huge Macedonian army of around 2500 men.
Luckily there was full brutii chunk right next to my army so in the pre-battle screen I saw them as reinforcements.
When the battle started, I was amazed to discover that there is no brutii army on the mini-map and right after that I got message about reinforcements delayed and that I have to fight all by myself.
As if it's not enough, I had no option to retreat my troops from the battlefield.
Needless to say my army was destroyed and I lost my 6 star general
Can somebody explain me what this all about???