Missing parcel and no assistance

On Friday I booked a parcel from Johannesburg kerk Street yo Worcester, when I got to the locker there was a parcel already in the parcel allocated for me I stood there not knowing what to do in my my I thought if I close this locke without depositing mine I will lose the R120 I booked it with and won't be able to open another one, so I deposited mine too in the same locker, then contacted the courier guy via WhatsApp, a lady immediately called me, I told her what just happened she assured me it's okay she will just tell the driver about the two different parcels. Later that day when tracking the parcel I realised that it's still not collected when then I contacted courier guy (pudo) via WhatsApp. They told me that when the driver arrived the locker was empty and no one thought of informing me. I was then asked details about the parcel which I gave then was told there will be an investigation. Today is Tuesday no one had contacted me, even sent emails, they are no longer replying to me on WhatsApp customer support. I'm frustrated as a small business owner the clients are not understanding. So I sent another parcel to my customers which is a loss for me. I've been with courier guy for years since I've started my small business. Moved to Johannesburg in January and I experience this, how is it possible to give two people the same pin