TAP - Misleading call center agent

On Dec 15, we logged in to our account for adding an extra luggage to our flight and saw a message that out flight is cancelled and we need to contact TAP call center. As per the message, my husband called TAP and learnt that the flight is not cancelled but the schedule is changed.Than he asked the call center assistant if it is possible to cancel the flight since the new time is not suitable for us. She confirmed that it is possible to cancel with full refund of the ticket costs. So my husband asked for the cancellation and we booked another ticket from another company. 1 day letter the same call center assistant called us back telling the refund is not possible. When we said that based on her confirmation from the day before we book another ticket and this is her fault. She confirmed that it is her fault and we can initiate a complaint on their website. On December 16 we initiated complaint number 2018 / 461921. After not hearing from them, we initiated another complaint 2019 / 49345 and still no reply. Whenever we call them either we cannot reach someone due to long waiting times or they said that complaint department is not working now and we need to call back later. This attitude is unacceptable. If the problem will not be solved we will initiate a complaint procedure to StarAlliance and local court.