Fedex is the worst international courier

Iv'e been trying to send a parcel to a very well known American family in New York. I was sent details on how to write a commercial invoice and I followed these steps properly. Two days later after the parcel was supposed to be sent overnight I get an email from Cheryl Roach saying the invoice was wrong and I need to fill out the relevant invoice and film declaration. Now why wasn't this given to me in the first place!! So I send it and after another whole day my parcel still hasn't been sent. She says the invoice I have filled out is incorrect!! So I speak to Melanie Goolam and now my parcel is still waiting to be sent. It has now been 5 days and my client in New York still doesn't have their parcel.. I need to know or be explained what I'm doing wrong on the commercial invoice but I'm still waiting for that information. Absolutely useless!!!