diff --git a/constants.py b/constants.py
index bac9422..ec5b4f5 100644
--- a/constants.py
+++ b/constants.py
@@ -5,7 +5,7 @@ BREAK_END_ENTRY_CODE_ID = 64
 
 PUNCH_COMMANDS = ("punch_in", "punch_out", "break_start", "break_end")
 
-SIMPLE_DATETIME_FORMAT = "%d.%m.%Y_%H:%M"
-SIMPLE_DATETIME_FORMAT_HUMAN = "DD.MM.YYYY_hh:mm"
-SIMPLE_DATE_FORMAT = "%d.%m.%Y"
+SIMPLE_DATETIME_FORMAT = "%Y-%m-%dT%H:%M"
+SIMPLE_DATETIME_FORMAT_HUMAN = "%%Y-%%m-%%dT%%H:%%M"
+SIMPLE_DATE_FORMAT = "%Y-%m-%d"
 SIMPLE_TIME_FORMAT = "%H:%M"
diff --git a/timebot.py b/timebot.py
index 61c1ede..c66d38c 100644
--- a/timebot.py
+++ b/timebot.py
@@ -145,12 +145,12 @@ class TimeBot:
         filters["filter"]["filters"].append({
             "field": "startDate",
             "operator": "gte",
-            "value": start_date.strftime("%Y-%m-%dT%H:%M:%S"),
+            "value": start_date.strftime(SIMPLE_DATETIME_FORMAT),
         })
         filters["filter"]["filters"].append({
             "field": "endDate",
             "operator": "lte",
-            "value": end_date.strftime("%Y-%m-%dT%H:%M:%S"),
+            "value": end_date.strftime(SIMPLE_DATETIME_FORMAT),
         })
         request = self.session.post(self.baseurl + "Entry/GetEntries", json=filters)
         request.raise_for_status()
@@ -197,7 +197,7 @@ if __name__ == '__main__':
     parser_punch = subparsers.add_parser("punch",
                                          help="use this command to punch in, punch out, or create break entries")
     parser_punch.add_argument("-t",
-                              help="type of time entry; this can be `punch_in`, `punch_out`, `break_start`, `break_end`",
+                              help=f"type of time entry; this can be {', '.join(PUNCH_COMMANDS)}",
                               default="punch_in",
                               choices=PUNCH_COMMANDS)
     parser_punch.add_argument("-s", help=f"timestamp in format `{SIMPLE_DATETIME_FORMAT_HUMAN}` or `now`", default="now")