How to determine the active pair on a DPI

Ouhla, if you really want to hear the complete history of my steamy adventure with SFR, I'm all ears (finally someone who listens to me).

It all started at the end of June this year.
I signed up for a 4K Fiber contract in-store (eligibility OK)
I got the equipment, plugged it into the coaxial outlet in the living room and... nothing
Well, I didn't plug it in right away, the wall socket is male and the cable socket is also male.
Anyway, I called them and they decided to send a tech.
Who explained to me during his visit (in an ENGIE van!!!) that he needed to call a team to "intervene at the pole."
And that they would call me for an appointment.

Okay, I need to set the scene a bit.
An old two-story building, bought and completely renovated by a single owner this year.
Previous tenants (2) were with Orange I believe but only for phone service.
Currently, there are 5 tenants and only one technical room from which all the ducts lead to and from the electrical and communications box (with DTI) of each apartment.
Maybe a photo?


I removed the cover from the DTI so you can see the connections.

And so since July 12, I've been waiting for the famous tech to call me back.
I've obviously followed up with 1023 and others almost every day.
Identical responses each time: he will call you back.
At the end of August, a text message informs me that my problem is resolved.
I must cancel my subscription due to lack of infrastructure!!!!!!!
Alright, fine, I decide to go for ADSL with SFR (yes, I know)
Contract signed over the phone on August 31.
The equipment only arrives at the delivery point on September 12 and the final activation of the line on September 14
On the 14th, I plug in the box and here.......... nothing, no internet.
Trust me, I've tried every outlet in the apartment where we could plug in RJ11 and other 45s. Nothing
Doubting myself, I went down to the technical room and found that the wire coming from my apartment (6 strands: 3 light blue, 1 dark blue, 1 yellow, and 1 white) is hanging limply in the air. (see 1st photo).
Called 1023, explained the situation and I hear the following phrase: a technician will call you back starting at 1 PM today. (confirmed by email and text) and that was Friday the 15th

I think you understand that when you suspect that everything depends (or at least I hope) on the connection of 2 wires, the integrity of the FT strips is the least of my worries.

In any case, thank you for getting this far.

I have a son who swears by the English Premier League, hence SFR
I can confirm that I do have a final number.
As for the bars, no worries, I will leave them alone.
Thank you for your answers.