In addition to reasonable interim expenses, inconvenience and loss of part of the purpose of the trip caused by the baggage delay is also recoverable.
The airline cannot limit their liability based on how long your baggage was missing. Reasonableness of interim expenses depends on the purpose and circumstances of your travel, and not the length of the delay of your baggage. The airline must compensate you based on the following precedents:
Providing receipts is not the only way to prove your damages, although it is the easiest one. A statutory declaration or a sworn affidavit setting out the losses and the reasons for the absence of receipts is sufficient as long as the expenses themselves are reasonable in the circumstances. You should send the airline such a declaration or affidavit, and tell the airline that it must compensate you based on the following precedents:
The first carrier and the last carrier are jointly and severally liable for baggage-related claims. The first carrier cannot insist that you claim damages from the last carrier. You should tell the first carrier that it must compensate you based on the following precedent:
Compensation payable under the Montreal Convention or the Tariff must be “paid in the form of cash, cheque, credit to a passenger’s credit card, or any other form acceptable to the passenger.” Travel vouchers are mere goodwill gestures, and do not relieve the airline from paying compensation.