The phone no longer recognizes my voicemail

I am unable to check voicemail because the phone no longer recognizes my voicemail password. It has also erased the message I give when the voicemail is activated by a caller. I've noticed in the upper left hand corner there is now a weird symbol beside the connection bars image. It is a white box with two blue boxes touching the upper right and lower left hand corners of the white box. What is happening?