about wifi technical

Olá boa noite 

 I used internet at my home but they're very very slowly, I called 16990 many times but nobody who support us. It's very terrible because I can't use internet on the first floor, just only ground floor have wifi. Who can help me contact with them? My phone number is 93******* at Vila Nova de Gaia.

I can't speak Português language.

Thanks.