How can I ask for a better definition of the tasks I get assigned?
Today the tasks are basically just a user story without any technical definitions on how it should be solved.
They expect me to find the solution by myself and once it's solved they will check if that was the way they want it or not.
This is somehow OK, but the problem is they change their mind between every task. So if I take the feedback from task A and apply it to task B, then suddently they don't want that for task B and can even suggest it to be solved as I did in task A before the feedbacks.
I have been working on cleaning up and implementing new functionality in a very central part of the product because it's very difficult to maintain (due to messy code; one class has more than 4k lines).
During this work I have implemented it the same way as it is done in other parts of the application and split things into smaller parts, so it should be easier for new developers to understand the code and it's more flexible to make changes without breaking the whole monolith.
But doing so, and talks during the development, make it clear they don't want it to be solved how it's solved (splitting up the code was agreed upon) other places with basically the feedback "we are now going reinvent the wheel and it might not be right to do it as it's done other places in the application".
This makes me kind of frustrated because I have no idea what they want and only thing I know by far is that they don't want it the way I'm solving it.
How can I ask them to write the tasks for "dummies" where somebody actually have a plan for how they want it to be solved?
Some background
I'm currently working as a 'sub-contractor' for a company because they are not able to hire the staff they need to be part of their team. During my time in the team their best developers have quit. Sometimes I wonder if this behaviour is because they feel threatened by "external people".
I have now canceled the contract with them and I just want to complete my work and leave in a clean way without looking like I'm just arguing with them.
Information added after asking the question
I have also made technical documents describing how I plan to solve it. This has never resulted in any feedback or yes/no, and if I ask about it when the task is completed, the answer is they have so much to do, so there is no time to go through it.