Temu complaint: Returns made impossible and not refunded

According to European law a consumer has to right to return items without explanation within 2 weeks.
Temu claims they offer 90 day free return.
The return label they provided turned out to be invalid at the post office. The return shipment could not be processed.
After taking to Temu for weeks (almost a few months) and trying to explain the problem, they finally understood the issue and claimed it was fixed.
I tried 3 different times with 3 different return labels. They were all invalid.
After being at the post office many times for nothing I decided to ship it with my own tracking label and paid 75 euro for the shipment of 2 packages.
After 2 months I again was in the same stressful communication with Temu for weeks trying to explain the issue.
They assured me the items would be refunded as well as the shipping costs.
Today the again closed a complaint ticket without solving anything ,after talking to someone for a week who still didn’t understand what was going on. They keep asking the same questions repeating the same untrue statements.

One package with a value of hundreds of euros has not been refunded still. They also did not refund the shipping costs.

I tried to help them return the items to them. I did not have to ship them on my own costs. It is their return system that does not work for Tenerife. No good deed goes unpunished. Now I lost the items and no money is refunded.

The story is much longer and the communication from Temu drove me close to madness.
But this was the short version.

Total running time of the complaints is 6 months now.
I lost about 500 euro.

Temu has great conditions published. But they do not fulfil their promises.
And they essentially break European Union consumer protection laws.
I will try to start legal actions against them.