RAM couriers and Vodacom

I had received a wrong device from Vodacom and they said they will collect it and refused me to drop it at one of the Vodacom stores so I was transferred to RAM couriers on a call to schedule a collection more than one and I had to be absent at work for the scheduled times it's now been three weeks I feel like they delaying the collection on purpose but don't understand what they trying to achieve. What a bad experience.