The statute of limitations has not expired. This is not a purely civil economic dispute, but also the relevant provisions of the CBRC. Regarding the repayment of the loan principal of 20 million yuan and interest by Company A, I think the statute of limitations has not been exceeded, because the legal representative of Company A, Li, signed the dunning notice and stamped the corporate seal of Company A, which can be regarded as that Company A has acknowledged the obligation to repay the loan, and the statute of limitations can be recalculated, and it is still within the statute of limitations on February 10, 2008;

Secondly, because the mortgage is unregistered and invalid, the bank can't enjoy the priority of compensation for the property mortgaged by Company C. However, if the liability for contracting fault is stipulated in the mortgage contract, the bank can pursue the liability for contracting fault from the mortgagor for the losses suffered. If the time limit for performance is determined, the time limit for litigation shall be counted from the date when the time limit for performance expires; If the time limit for performance cannot be determined, the limitation period of action shall be counted from the date when the grace period for creditors to require debtors to perform their obligations expires, but if the debtors explicitly indicate that they will not perform their obligations when creditors claim their rights for the first time, the limitation period of action shall be counted from the date when the debtors explicitly indicate that they will not perform their obligations.

When a bank brings a lawsuit to the people's court, it is a clear indication that the debtor fails to perform the repayment obligation.