This guide explains the different task status. You can view your task history here.
Credited – task completed successfully and b credited into available balance
Pending – task completed successfully and b credited into pending balance as task is worth more than 3000 b. This is to prevent fraud and misuse of Blockreward. Task will automatically unlock (when unlock time is reached as displayed in the task history) and b credited into available balance.
Rejected – task was rejected by the advertiser and b debited from the available balance