Hello @Kostusas 

Was there no adapter in your installation package with 4 pins which can be plugged in this socket?

You can also open the socket and show us the wiring, maybe the problem is inside, make a picture and upload it here.

Do you have the little connection box with only a red and blue wire in it? Maybe that can be usedand have you checked that your connection should be active today according to your T-Mobile account or sms/email/letter you received?

Thanks for your response.

First thing first, I did indeed use the 4 pin adapter (number 2 in the list of things I tried above). However, the internet (globe) symbol did not light up once and consequently, there was no internet connection. It makes sense because as you’ll see in the photo, the 4 pin socket in my house was just for show:
 

I am not sure I follow regarding the connection box with red/blue wires in it. Is this supposed to be somewhere in my house or does it come with the installation package?

According to the webpage and the SMS I got in the morning today, today should be my installation day. However, having said that, I am still able to use my old TELE2 internet which is supposed to be cancelled today. So it could be that the connection has not been switched yet, despite what other sources might say.

@Kostusas

Remove the DSL cable which you connected.

There should be a white connection box in the installation package you received.

Connect the black and transparent wires to the connection box, take the grey DSL cabel which is also in the installation package and plug one end of the cable in the connection box and ther other end in the DSL port of the modem.

If it doesn't work remove the black and transparent cable, on the photo you placed above there is also a white and transparent wire on the right side which are twisted. Those can be tried instead.

No luck in both cases as you can see from the photos.

Also, if I use the old modem from TELE2 with the black/transparent wires (the bottom photo), I can recover my previous internet connection… Is it possible T-mobile has not switched my lines yet?

Is it possible to request a technician to visit?

Yeah sure please wait for a moderator to reply, but it looks like there is no signal on the line.

Hi @Kostusas, thanks for alerting us about the issue you're experiencing! I'm happy to see that you already spoke with a colleague of mine over the phone, and that a technician is coming by soon. I wasn't able to find one, but if you happen to have a T-Mobile Mobile subscription, please give me a heads-up and I'll try my best to provide you with extra data. Feel free to let me know if there's anything else, and have a nice day.

Sadly, I do not have a T-mobile phone number, but I appreciate the kind offer.

Also, there seemed to have been some delay and my previous internet provider TELE2 only cut the line today (rather than on the 6th as was planned). At the risk of sounding ignorant, could this miscoordination be responsible for my issues? When I plug in the modem now, the previously used line (black/transparent wires) doesn't even light the globe symbol red (which it did previously as seen in the above pictures).

Thanks for letting me know @Kostusas! Since we use the same internet line and network operator in your area as Tele2, this should not pose a problem. I'd still recommend the visit of the Guidion technician, but it could be that a technician of the network operator also needs to come by. In the worst case scenario, this should be solved before the end of the week, but likely it will be solved on Wednesday. I'll keep a close eye, and have a nice day!