Just started PhD, feel lost and abandoned I started my PhD some months ago. My advisor was also my Master's advisor. He was impressed by my skills and passion so I enrolled in a PhD program with him. 
What happened is that my topic changed quite lot and he didn't tell me clearly before enrolling. Basically my master thesis topic is in the trash for him now (FYI we published in a top conference with that). He wants to work on a totally new idea, on which not even him has the right expertise, so basically I have to study a whole new state of the art, have the ideas, acquire the skills and present the results - why do I even need a PhD advisor then..?

I feel lost, abandoned (I have nobody, nor other PhDs or PostDocs to work with) and hopeless. Yes, I tried to explain my advisor that I'm not excited by the new topic, but he's like "I pay you for this, so you'll do this". 

Any experience on situations like this? Should I quit and say goodbye? Am I wrong expecting more by a PhD advisor?
You have good reasons to feel abandonned, and it is the good moment to decide whether or not to pursue a PhD. This decision is a difficult one to make, and you will need to reflect on your professional goals and alternatives for you. Starting such an endeavour, and not being excited by the subject is a big deal.

No, you are not wrong to expect more. A PhD student is not a researcher you pay to have something done. A PhD student is someone with some skills, but that still need training.

There is things you can do if you want to continue your PhD on this topic:


Ask your advisor to include a coadvisor with expertise in this new subject. You could even try to find yourself a coadvisor.
Find course on this new topic, either at your university or at another. Sometimes it is possible to take classes at another university and have it include in your program. It depends on your country and university.
Make the subject your own, by developping your questions around it. A little bit difficult when you are starting, but this is doable.


... and this is not an exhaustive list.