If the signature wasn't saved / you don't see date stamp, unfortunately, there is nothing to recover. Or, if you hit save signature, but don't see date stamp, the signature did not save.
The only way to rectify this is to print out the billing document and manually send it (via FedEx) to Genpact. The address for Genpact is...
335 New Commerce Boulevard
Hanover Industrial Estates
Hanover Township, PA 18706