Yes, I feel the same way you do.  I've had a couple of Sendle parcels sent.  Some were not collected till one or days later.  I once had 2 parcels left outside and only one was collected.  I messaged them to let them know that one was collected.  Had not response.  The other was collected a day later.  Not sure if that was because of my message or their system telling them a parcel needs to be collected.  The tracking times seem all over the place as you have mentioned.  When I called Couriers Please to tell them that a parcel was picked up without a scan they gave me the same response that the driver may have been busy.  They also mentioned that they driver might of thought both parcels had the same tracking number and so only one was scanned even though they were 2 very different addresses.  In the end the parcel was received but they seem unreliable and I was so stressed.  Nothing runs smoothly.  So I will stick with AP.