To disbelieve something is to "not believe" something and implies to "believe something else".
No, that does not logically follow from the premise. To disbelieve/not believe one specific thing does not imply that something else is believed or, that something else is disbelived.
We either know or don't know; believe or don't believe. When we do not know, it does not require a decision and is the absence of information or understanding that would enable one to formulate an opinion.
The 'reasoning' is faulty because it's incomplete. When one doesn't know, (has incomplete/unsufficient/inaccurate or no information), a decision is required to either proceed on the basis of incomplete/inaccurate/no information or, to attempt to obtain additional information which would contrubute to a more informed "opinion". If one decides to proceed on the basis of inaccurate or no reliable information, (blind faith, for instance), that decision forms the basis for an uniformed opinion.
When we don't believe, though, it is a refusal or inability to accept and requires an active decision about the material being considered. Disbelief is not ambiguous, it is precise and unambiguous (it doesn't require knowing a substitute for that which is not believed, it is just a belief that that which is not believed is not real of true and ergo, something else is).
That's at least partially correct, however incomplete. The "refusal" to belief in nonsense, (that which lacks any evidentiary basis or, has an ambiguous basis), to a rational decision. Accepting/believing in something which lacks an evidentiary basis requires an irrational decision to do so.
The distinction being conflated by your incomplete assertion is that the
belief itself is distinguished from what is allegedly
believed in. This may seem subtle for some, (like those unable/unwilling to distinguish between a
"believer" and a conceptual
belief), however they do have parallel aspects.
You try to imply that disbelief is an ignorance or unawareness ...
No such thing was implied or, could be rationally inferred from prior statements. This is due to your penchant for fabrication and has no evidentiary basis therefore, I do not believe you.