"I could not."

Translation: Saya tidak bisa.

[qZzR1d1d]

Could this also be ‘I cannot’?

[IchbineinKnopf]

Correct. :-) Without context or any modifying adverb of time, such as "kemarin" (=yesterday) or "tahun lalu" (=last year), it could mean both.

Source: my girlfriend (native) :-D