Originally Posted by SK AAR

There is a big difference in cancelling and requesting a refund of a ticket due to cancellation or delay or reimbursement of expenses incurred to delayed luggage than to asking for reimbursement of a replacement ticket you have purchased on your own. To my knowledge the DOT rules do not protect you against the latter. You simply can’t just purchase a new/presumably much more expensive ticket with another airline just because you are not happy with the rebooking options offered to you or because you can’t get in contact with TK.