Best Trade Solution

I've lost full sets of b/l. I know I can request reissues nice of originals or request clearing of goods without original B/l, but shipping company wanted me to sign letter of indemnity. I don't understand why the letter of indemnity covers 200% of value And requires my bank to countersign. Does this mean I need to put up security in order for them to counter sign this indemnity? How can I minimize lost of B/Ls going forward? What if the B/l is consigned to buyer? what happens if this is under letter of crediT and bank already discounted bill for me.