Signed for surety

If you are a surety for the defaulted loan amount then the court can pass an order to recover the same through your employer. 

I can't able to pay that amount is there any other ways to solve this or possible to reduce that amount

You would have been impleaded as one of the defendant in the case, you did not appear in the case hence you have been set exparte in the case and the execution proceedings are going on against you in the absence of judgment debtor.

Therefore as you have lost the opportunity to contest the case, you may have to compromise with the lender alone or to face the law accordingly

Surety cannot be enforced unless it is invoked through the due process.