4 weeks and no receipt

A friend has submitted an application for green card replacement to INS. He has sent it via FedEx and FedEx records show that the application was received at the Houston office on February 24th. As of today, my friend has no receipt from the agency, however. What should he do now? Wait or send the application again? Has anybody else noticed delays in receipt issuance?

A friend has submitted an application for green card replacement to INS. He has sent it via FedEx and FedEx records show that the application was received at the Houston office on February 24th. As of today, my friend has no receipt from the agency, however. What should he do now? Wait or send the application again? Has anybody else noticed delays in receipt issuance?