From the document you linked to:

A re-elected Liberal government will also reduce the cost of wireless services by 25 percent within four years, putting $1,000 back in the pockets of the average Canadian family every year. This will be done by:

To Scheer's point, they have no real plan to accomplish this. It's just words.

Working with telecom companies to offer plans at globally comparable prices;

Again, government shouldn't be telling companies what to charge. They should be ensuring a free competitive market, the prices will take care of themselves.

In short, this Liberal statement means effectively nothing.

Encouraging Canadian competition in the market, and allowing the CRTC to step if that competition isn’t leading to lower prices; and

Yes. I support this. With the possible exception of CRTC involvement. The less government and bureaucratic interference, the better for the consumer.

This statement is directionally correct but, again, it's not a "plan". It doesn't mean much at all.

Prioritizing consumer choice and affordability, and not simply the highest bidder, when awarding new wireless expansions.

Good statement. I support this statement 100%.