Cannot delete Room Calendar item with exchagelib code - exchangewebservices

Question

My problem looks weird.
Exchange 2010 SP1. Code looks for conflicting record in Room Calendar and suposed to delete it.
Code looks like:
#DELEGATE also doesn't work
roomAccount = Account(primary_smtp_address=room_mailbox, config=config,
autodiscover=False, access_type=IMPERSONATION)
items = roomAccount.calendar.filter(start__gt=now_with_past)
for item in items:
if (start_dt_ews != start_dt_remote or item.subject != remote_record_subject or duration != remote_record_duration):
has_conflicts = detect_conflicts(roomAccount, item)
if has_conflicts:
process_conflict(item, 'update_conflict')
remove_meeting_data(item, item.organizer)
continue
def detect_conflicts(roomAccount, item):
try:
has_conflicts = False
if item.conflicting_meeting_count > 0:
if item.start_dt != item.start:
has_conflicts = True
return has_conflicts
except Exception as e:
trace_back = traceback.format_exc()
log_str = "Error in process_service " + str(e) + " " + str(trace_back)
Logger.error(log_str)
return False
def process_conflict(item, category):
if item.recurrence:
conflict_notify_and_delete(item, category, True)
else:
conflict_notify_and_delete(item, category, False)
Logger.error(item.subject + " meeting conflict error.")
def conflict_notify_and_delete(item, category, serial):
send_email(item.organizer, category, (item.subject))
try:
if serial:
item.delete(affected_task_occurrences=ALL_OCCURRENCIES)
item.save()
else:
# doesn't work
item.delete(send_meeting_cancellations=SEND_TO_NONE,
affected_task_occurrences=ALL_OCCURRENCIES)
# or also doesn't work
item.delete()
# or raise trash folder absense error.
item.move_to_trash()
# or raise trash folder absense error again.
item.soft_delete()
#abrakadabra atempts with rescheduling and subsequent deletion raise
# "Set action is invalid for property. (field: FieldURI(field_uri='calendar:StartTimeZone'))" error
item.start = UTC_NOW() + timedelta(days=6000)
item.save(update_fields=['start'])
item.delete()
The strangest fact about all this - any of delete() processing simply silent - no errors, no exceptions, everything looks like to be just fine while actually nothing is deleted of modified.. Second strangest fact - sometimes but not every time i'm trying to item.save() after item.delete() , it raise " AttributeError("Folder must be supplied when in save-only mode")", but item may be deleted at once. And may be not :((
This weird things happen only in part of code that process conflicting calendar items. Notconflicting items processing is fine - deleting and modifiying are ok.
Does anybody has any idea, what is going on and how to finally delete conflicting record from Room calendar without canceling a meeting from organizers's calendar - we do not want user to loose his item and information inside it? I've tried to google EWS setiings that can cause such weirdness but with no luck :(