Hallo, kann ich Englische Fragen in diesem Forum stellen? Wo ist sonst der richtige Platz?

I was promised in black friday certain promotion (all included e.g., taxes and other extra costs) due to my company agreement with telekom.

However, I received an invoice by post, that was asking me to pay more than what I agreed with the vendor at Westenhellweg, Dortmund shop. 

Even with a 20% reduction of the price per month it is not what I was promised.

I am feeling kind of tricked and disappointed by the telekom vendor.

I could have had a better deal on black friday if I would have made it online. I showed it to the vendor, but he promised me a better deal by making it physically/directly with the store (my German was not good to read all the contract document agreements, but I didnt see another price that was not what I was promised).

The vendor of the shop is not answering my e-mails and neither telekom.

Is there an e-mail or contact that can follow-up this issue?

Please, is there someone that can help in how to proceed with this issue.

Best regards,

Jordy Goyos