Is accusing me of having an incorrect intention considered an injustice if my intention was sound, and will a supplication for something unrelated to the accusation, such as marriage, be answered, even if my clothing is unlawful?

It is not permissible for a person to judge the intentions of others. Therefore, whoever judged your intention and wronged you by doing so has erred. It is better that you forgive him, but you are also permitted to supplicate against him, for the supplication of the wronged is answered, so long as he does not transgress in his supplication. It is recommended for a Muslim to supplicate to Allah for all their needs, including marriage, while taking into consideration the conditions for the acceptance of supplication and avoiding obstacles to acceptance, such as consuming unlawful earnings.