DHL International BAD service - no collection after 2 days. Paid for a express delivery

Recently booked a parcel with DHL. They ensured delivery in 6 days to International location. I paid all the necessary fees in advance, booked the collection and now I am still waiting for them to collect the parcel. Tomorrow it will be day3. I have contacted them numerous times to enquire about collection and they ensured me every time that collection will happen within the next few hours. Still waiting. They have subcontracted RAM couriers for the collection so I suppose the culprits are actually RAM couriers, but I have a agreement with DHL and hold them responsible for not pressing their subcontracted party in collecting the parcel in time.