Foreclosure after Chapter 13 discharge

Hi, I am so worried and I dont know what to do. My husband and I file chapter 13 bankruptcy in september of 2005. We just now got our discharge papers around the 1st of Sept. 2010. We got the letter from the trustee informing that all of our bankruptcy debt had been paid and congradulating us on finishing our bankruptcy. Our mortgage arrears were included in our bankruptcy along with our normal monthly payment so the letter said that we should start paying our mortgage to the mortgage company instead of the bankruptcy trustee. I went to the mailbox on Sept. 18th 2010 and got a letter from our mortgage company. I thought it would be a statement informing us of where and when to send in our payments. To my horror it was not, instead it was a letter telling us that they are going to foreclose on us in 30 days unless we pay over $9000.00 before October 17th. I am so confused because I thought that all of our debt was included in our bankruptcy filing and had all been paid. I called them and they said to fax their research dept. to see where it is coming from and that could take 10 to 15 days.
My question is: Can they foreclose on us after we have been discharged especially since we got the letter from the Bankruptcy judge saying everything was paid and we even have proof that they were sent a letter in April to let them know they were going to discharge us and if they had any disputes to enter them now and they did not so the the bankruptcy judge went ahead with the discharge.
Please help.....I dont want to lose my house