英语翻译Negative balances represent a credit and no payment is d

英语翻译
Negative balances represent a credit and no payment is due for that term.
Positive term balances represent a balance that is currently due.
A negative net amount represents a credit that may have been used to pay charges on another term.
第2句中的balance是欠费的意思？第1句和第3句中的credit是一个意思吗？余额的意思？