Lost ICMP

[carrerasg]

Hello,
I've been using HE for about 2 months now I think. Without any problems at all.  Just recently, it appears that my provider has started blocking ICMP for some strange reason.  I didn't really notice until this afternoon when I couldn't surf IPv6 sites that I usually do.  I'm having a heck of a time explaining to customer service what the problem is.  It doesn't help that they speak spanish and I'm pretty much limited to conversational spanish.  Anyway, I have two questions that I need to ask:
1) How long after losing ICMP does it usually take before my tunnel breaks?  Is it usually immediate or does it take some time?  This might help me better to determine when the blocking actually started occurring.
2) Will my tunnel still remain configured even though it can't be pinged?  How long will HE hold it for me before tearing it down completely?
Thanks,
Glen

EDIT:  I have since been able to convey the problem and they corrected the issue.  I'm still interested in the answers to the above questions though, just in case it happens again.