Sometime the problem will be happened with the cable modem. You can try to reset it (disconnect the power supply with it) to settle the problem by yourself. If the problem still happen, I think the engineer must come up to check and fix.
On the other hand, i-cable always arrange the engineer (out source engineer. very poor) come up to check. They never provide the phone support to you.
Sometimes your case happened with my home. It might be happened with their network equipments. After they repaired (around few hours or a day) the problem was gone. So I never request they come to check cos I needed work within office hours.