Is It Possible To Purchase 5.4 Million Pennies?

I did have an attorney review the mortgage before we signed it. That attorney said we should set up payment arrangements to avoid any other problems, pay him first, and later sue him to get the money back. We made our payments for 12 months with a balloon being due later. When it came time for the balloon we wanted to negotiate a settlement for the change orders rather than suing him and were willing to split half of them. He refused and hired an attorney first to threaten foreclosure on a property in which we have significant equity, we consulted an attorney who said we signed away any disputes to the amount when we signed the mortgage (contrary to what the other attorney had told us).

Again, the change orders he submitted to me came one month after the project was complete and only after we missed our final payment for the work. At that point in time we asked him to set up payment arrangements and he replied he wasn't a bank and would not accept any payment arrangement. In the email he sent to me with all the change orders (one month after the project was complete) he said, "since I never heard back from you on the change orders I assumed you approved all of them". He even admitted in his email that I never approved them!

However, I am now being advised that I have no remedies because I singed the mortgage for the full amount and should have fought him at that point in time. (we signed the mortgage because it was one year after the project was done and he was going to enforce his lien if we didn't, although he refused a payment plan one month after the project he later required one through the mortgage 12 months later, all part of his plan?). We tried to negotiate the change orders with him at that point in time but he said the amount is not up for negotiation and we must sign or he will foreclose with the lien (again, our contract attorney said to just sign it now and fight later).

Was I advised incorrectly by my attorney? What can I do about that?