If denying the obligation of khums means a denial of its obligation in the unused amount of the yearly income, then this does not affect the person being regarded as a Muslim. However, denying the khums in an absolute way is a clear rejection to the Quranic verses and the tradition of the Prophet (peace be upon him and his holy progeny).
It is permissible to make use of the treasury bills and one must not intent to make a deal with the government bank but rather intend to make use of this mechanism. When collecting the money, it should be on behalf of the religious ruler i.e. the just Mujtahid.
<p style="text-align: left;">It is not permissible to use sex toys that are separate from the body in such a way that the enjoyment is because of the toy. Using the condom in such a way that the enjoyment is due to the penis itself is permissible.</p>