So the balance without interest by the 7th year is : 7261.57 (2 DP) Subtracting the interest of 0.5% (assumption) : 7261.57 * 99.50% = 7225.26215 or 7225.26 (2 DP)
Note this way is extremely time consuming, I was just showing the process. I may not be right though, if my logic seems right, use this answer.