Since I'm traveling with essential medicines and medical equipment it is key for me that my carry-on luggage is allowed to be carried into the aircraft cabin, so that it's available to me at all times, and not lost due to accidents or theft.
Last times I flew my carry-on-luggage was gate-checked, meaning that it received a "Delivery at aircraft" tag and was stowed together with the checked-in bags underneath the aircraft at the time of boarding. Only at one time have I received a corresponding receipt. When complaining, the gate-check personnel told me to talk to the staff on the tarmac, who often don't understand English. The aircraft crew is inside the craft.
This means that I cannot access my medical equipment in case of an in-flight emergency. And, if the "delivery at aircraft" bag is misplaced or stolen (which has been reported to happen to others), I have no proof I had the bag in the first place, and I have none of my medicines while in a foreign country.
What can I do to ensure that I am allowed to carry my carry-on luggage into the cabin?