Amazon. DHL does not pick up

Chronicle of an inefficiency.
31-3-2022
I requested on 31-3-2022 the collection of a return for an item and I received confirmation from Amazon by email with the date of collection 1-4-2022 from 9 a.m. to 6 p.m. I had chosen DHL as the courier.
1-4-2022
I waited all day at home for the DHL courier to come and collect the parcel, but no one came.
2-4-2022
I received this email from DHL :
Dear Customer, the attempt to collect your return by the DHL courier was unsuccessful. EASY RETURNS at a DHL Service Point To proceed with your return, you can go with the same label to the DHL Service Point that is most convenient for you, check opening hours - also evenings and weekends. Find your nearest DHL Service Point by clicking here.
EASY RETURNS at a DHL Service Point? So I am supposed to look for the nearest DHL address and bring the parcel to them? This behaviour by DHL is unacceptable.
There is a questionnaire on Amazon's website about the satisfaction of the return procedure and I filled it in explaining the situation.
I called Amazon's toll-free number 800 145 851 which replied "We can no longer receive requests at this number, please press 1 to receive an SMS". I received an SMS saying "Amazon Customer Service: you can contact us by clicking https://amzn.eu/gdrx2pa or by selecting Customer Service on our website or from the Amazon app menu.
"Customer Service" is located at the bottom right of the Amazon page.
Contacted Customer Service and replaced DHL with SDA. The procedure is very easy and I completed it in one minute.
Interesting note:
- for DHL collection, you need to print two forms and give one to DHL.
- for SDA collection you do not have to print anything. SDA carries the label.
So the recommendation is to always choose SDA.
I am waiting for the scheduled Amazon pickup on 4-4-2022.