Arçelik Did Not Replace My 3230 SFC Water Filter for Months

I signed a 3-year contract with Arçelik for filter replacements for the Arçelik 3230 SFC water purification device and paid the full amount in advance. Over two years, the filter was replaced four times, leaving me with five remaining replacement rights. However, for the past 10 months, they’ve repeatedly given me scheduled dates but never showed up, claiming the filters are not being produced. I’ve called the service multiple times to file complaints and request a solution. Each time, the date is postponed by another month; yet no replacement is made, nor is a refund offered for my remaining five filters at the current price. This situation has exhausted me, and I am urgently asking for help.