Travelstart's inaction forfeits possibilty of flight postponement

I booked a flight to Germany with Travelstart which I had to postpone due to Germany's quarantine regulation due to the the Omicron-variant. I contacted Travelstart via their WhattsApp Line about 2 weeks prior to departure with the request to contact me regarding this flight. I made use of all available communication channels in order to make Travelstart aware of my predicament, but nobody ever got in touch with except the automated responses, promising me several times that someone would be in touch with me within the next 72 hours. This unfortunately never happened and Travelstart missed the 48 hour deadline to rebook my flight. In a desperate attempt to save at least some money, I used the option 'emergency 24 hour cancellation', upon which my flight got cancelled and I was promised a refund of about 20% of the flight's original value. Eventually after my scheduled flight one of Travelstart's agents finally got in touch (by WhattsApp) with me to find out how they could help me. All they could offer me were their 'apologies for the delay' and no indication of willingness to compensate me for the loss Travelstart incurred me.