Turkish Airlines Seat and Pet Transport Issue

I purchased a seat twice, and my flight was canceled. I selected a new flight, but the seat from my previous flight isn't transferring to the new one. Additionally, for some unknown reason, I can't get pet transport rights. The first seat I chose had extra legroom, and I paid ₺650 for it. Then, I found out it wasn't suitable for pet transport and chose a standard seat, paying ₺300 for it. My flight was then rescheduled to another day. I updated the dates on the ticket management page. The seats I paid for on the original flight should have been transferred to the new flight, but I was told this wasn't possible and I needed to get a refund first. Then, I was told I would need to purchase the seats again. I contacted the call center four times, and three times I was told, 'Call us later. We can't process this right now.' Now they are asking me to pay again; this is too much. When it comes to taking money, they are the fastest and the best; when it comes to action, no one knows anything. What kind of system is this? I don't trust Turkish Airlines' cargo department for pet transport. I want to carry my dog with me in the cabin. I need assistance from an authorized person. I want both the seat I paid for twice and my dog with me. I am requesting help for my flight t3wj6g, Istanbul-Sinop, Sinop-Istanbul.