Diesel regeneration particle filter

I live in Australia and have a 2016 diesel Porsche Macan. Since getting it I constantly get the notification regarding the diesel regeneration particle filter which comes and goes and eventually the glow plug light comes on and tells me there is a problem with the engine and to see the dealer. Last time was only about two months ago and I had literally had a service three days before it happened and they charged me $200.00 to fix it and now its back again. I do not drive short distances which is what they tried to tell me was causing it and I do not know if it is something they are deliberately not fixing to get me to come back or if there is something I am able to do myself to fix it. I am getting really tired of this I have never had this problem in any other diesel Porsche's or other I have had. Hopefully you can help me out I would really appreciate it. Thanks