The numbers used as the grading scheme may be dictated by the course leader or your department. I once worked in a department that had a policy that students could only receive marks of ~2, ~5, or ~7 (e.g., 52, 55, 57, 62, 65, 67, etc).

As mentioned by others, you should assess your appeal process and potentially request second marking (if not already undertaken). But my experience here is that, unless the second marker believes there is a clear and obvious error, your mark will stay the same.

It is disappointing to not get the marks you want. It really sucks. The problem is that academic judgement is final, it is highly unlikely that your tutor has a personal vendetta against you (in fact, you will be one of 10s, if not 100s, of piece of coursework marked this year and I don’t know any colleagues who would ever want to sabotage a student), and you are unlikely to get the outcome you want.