I don’t speak Spanish very well, but I didn’t see names other than Freedom in the snippet of Contract you posted. The privacy policy should tell you who they are allowed to share your data with explicitly; read that and tell them who you don’t consent to sharing your data with (edit: find the privacy policy on their site in English: freedominternet.eu/privacy-policy, the PDF link loads something but it’s not a PDF)
Do you have any other options for internet service? Even if you get the promotional offers removed from the contract, you’ll have to keep an eye out for offers from new organisations and if you get any, contact them to find out how they got your information if you can. Basically, they might sell your data anyway, so you’ll have to be ready to protect yourself if they do.