Semi basement reception

I, recently switched from Public Mobile(Telus Network) to Videotron. I used to have an excellent reception in a semi basement, never had any problem. With Videotron, I noticed that half of outgoing calls does not pass through. Also, I do not receive some incoming calls. I cannot even reach my voicemail many times, very frustrating.. However, I have no problem out of semi basement.

I wonder if there is any solution to this. I live in Lachine area.