Gfs express courier

The worst people ever. They threw my parcel over our wall and that while im not home. When i phoned them the lady could not answer me who signed as no one signed she then put the phone down in my ear and then blocked my number. I need something to be done to this company people this is my 3rd time having a problem but this time its worse how do you throw a parcel over the wall.... There's no email or telephone number