Verizon boss Lowell McAdam, his company facing slowing sales of mobile phones, made a proposal to acquire cable-TV giant Charter Communications in recent months, three sources told The Post.

The offer — valued at between $350 and $400 a share, and well over $100 billion, according to two of the sources familiar with the move — was rejected by Liberty Media-controlled Charter CHTR, +0.45% because it was too low — and because Charter was not ready to sell.