Never delivers

This courier company is very unreliable they lie and the delay with your parcel or cargo.. And they lie and say they tried to get hold of the consignee. But they actually never try to contact you or locate you... I've been having a parcel stuck with them for a week now and it's alwsys on route for delivery but never gets to me I'm tired and I'm looking for ways to sue the for this huge inconvenience and theft