Let $c\phi_{ k}(n)$ be the $k$-colored generalized Frobenius partition function. By employing the generating function of $c\phi_{ 6}(3n+1)$ found by Hirschhorn, we prove that $c\phi_{ 6}(27n+16)\equiv 0$ (mod 243). This confirms a conjecture of E.X.W. Xia. We also find a congruence relation $c\phi_{ 6}(81n+61) \equiv 3 c\phi_{ 6}(9n+7)$ (mod 243). Moreover, we show that $c\phi_{ 6}(81n+61) \equiv 0$ (mod 81), $c\phi_{ 6}(243n+142) \equiv 0$ (mod 243) and $c\phi_{ 6}(729n+ 547) \equiv 0$ (mod 243). We further conjecture that for $n\ge 0$, $c\phi_{ 6}(243n+142) \equiv 0$ (mod 729).
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