Based on what you have mentioned, it seems that DHL is the far better service when it comes to the customs-clearance process. I have recently placed an order for a mobile phone and my phone is currently stuck at the DHL warehouse, awaiting for customs clearance.
The customs required me to provide the TRCSL approval and I provided it. TRCSL does provide the approval via email and it can take about a week for the TRCSL approval. As for the ICL, DHL informed me that the ICL is not required for my shipment. Once the item was detained, DHL delivered me a set of documents containing the required information and I handed them back on 11th November. Apparently, one of the documents which I submitted, had not been accepted by the customs and they asked me to re-submit that document and I submitted it yesterday. I am still waiting for the clearance and there is certainly a big delay in clearing the items nowadays. In a nutshell, my phone is at their warehouse since 4th November and I am yet to receive the parcel. Let me know if you need to know anything regarding the process which I have undergone so far.