"ti" is for male and alive nouns in nominative
"Ty" is for male and alive nouns in accusative
as well as for male and non-alive nouns and for female nouns both in nominative and accusative.
"Ta" (in plural) in for neutral nouns also both in nominative and accusative
No, unfortunately, these "recordings" are automatically generated by a TTS system which is produced by an external vendor. We have no control over it at all. There are much more serious defects that no-one repairs.
You can suggest disabling the audio exercise if it is too hard or even impossible to recognize. I do not think it is the case here.