How can I cancel a DSL contract

I am very disappointed with the DSL internet service.
First time, the technician did not find the junction box.
Next scheduled 10 days after, I scheduled for the morning and the technician showed up at afternoon. Nobody was at home.
Then, third scheduled, more 10 days after and the technician did show up.
I signed the contract more than 50 days ago and I still don’t have DSL internet access.
I want to cancel the contract.
This is the worst DSL service ever!!!!
How can I cancel the DSL contract that I never used???

Thank you