Can I demand the contract from my telephone company?

I am subscribed to a telephone service by which making calls abroad is cheaper. I hired the service by phone, and now I want to cancel it because I can call using my wifi without the need of having a special service. However, each time that I call they say that I have to call to a different number, or that they have already dealt with my request when it is not true… Last time, they asked me for the contract, but as I hired the service by phone, I do not have it.

Is the company obliged to provide me with it if I ask them for?

Yes, they are. You can ask them to send the contract in writing with the clauses, and it must include the requirements to cancel the service and the means to do it. In normal conditions, the request to cancel the service sent by fax is enough.