unreliable

an unreliable source of information

The process is cumbersome, expensive, and unreliable.

Some things break entirely, and other things start getting sticky, slow, and just plain unreliable.

Like all history books, though, they can be unreliable.

But sorrow is unreliable in that way.

Stupid, unreliable vampire, I thought to myself.

However, he can be a little unreliable sometimes.

Their main complaint is the unreliable electricity supply.

Phone lines without electricity would be unreliable, too.

They are expensive to acquire, unreliable and fiddly.

The Bluetooth is still so unreliable.