Does a person get credit for fasting on Tasu'a and 'Ashura if they intended to fast on Thursday as a voluntary fast, and fasted on Friday with the intention of Tasu'a based on an incorrect calendar, and did not fast on Saturday after the error became clear to them?

Scholars have differed regarding the obtainment of the reward for fasting 'Ashura' or Tasu'a for someone who fasted them with an intention other than for these specific fasts. Some scholars are of the opinion that the reward is obtained due to the act of fasting itself, while others do not hold this view due to the absence of the specific intention for fasting them. We hope for the questioner that he obtains the reward for fasting 'Ashura' and Tasu'a for the fast he observed, in addition to the reward for his intention to fast them.