I sent in my 2010 amended tax return via mail June 6,2013. It's been 9 weeks and I haven't received it yet and when I call to check on it, the recording says it not in the system. Should I be concerned that it got lost in the mail and if so, what do I do?

Did you check here (some amended returns are not in the system):
Where's My Amended Return?

It can take up to 12 weeks to process an amended return and a few extra days to receive your refund. If you haven't received it by 13 weeks, call again and talk to an agent

Always send your paperwork registered/certified to have proof of mailing and a receipt when they receive it!

Actually, for the past year, the processing time for amendments has been as long as six months. I suspect that budget cuts are to blame.

Regardless, wait until the end of September. If the amendment is not on Where's My Amended Return? By then, re-submit using registered mail.