I am sorry to hear that your girl Majick is drinking and urinating dark orange colored urine excessively, losing weight and eating poorly. I understand that she was previously diagnosed with kidney failure and prescribed a food to help her kidneys function better, but that she is not fond of the food.
Early on with kidney disease changing the diet to support the kidneys may be all we need to do. But if she is refusing to eat that food it cannot help.
Was she eating poorly too before her diagnosis?
How long has she been sick/showing symptoms?
Because she is losing weight that indicates a significant, chronic disease and an examination and some further testing is needed as soon as possible.
Cats tend to have a higher incidence of kidney failure as they age. That can lead to nausea, vomiting, and gastrointestinal ulcers, a loss of appetite and weight loss. So we definitely want to recheck that, but given that she has been sick long enough to lose weight we do want to make sure there isn't more than one thing happening. Cats that don't eat well for a period of time can get into trouble with hepatic lipidosis. This is fatty liver disease caused by overwhelming the liver with fats being broken down for energy to live when they don't eat such that it cannot perform normal functions. This is a secondary disease, but it can be deadly and needs to be aggressively managed. Her dark colored urine is a probable indication that she is developing secondary liver disease and jaundice.
It is also possible that she has cancer which is affecting her kidneys and liver. Lymphoma is very common in cats, could affect multiple organ systems and would lead to increased drinking and urination too.
I would recommend a complete blood count and biochemistry profile with a T-4 (thyroid hormone level) as well as a urinalysis to start. Depending upon those results an abdominal ultrasound may be recommended.
In the meantime you can try giving her an acid reducer to see if that helps reduce nausea and gets her eating. You can give either:
1) Pepcid ac (famotodine) at a dose of 1/4 of a 10mg tablet per 5 to 10 pound cat every 12 to 24 hours
2) Prilosec (omeprazole) at a dose of 1/4 of a 20mg tablet per 10 to 20 pound cat every 24 hours.
These are very safe and can be used long term if necessary.
You might also try feeding a homemade bland diet to see if that helps stimulate her appetite. Ideally she would eat a diet formulated for kidney failure, but right now we just want her to eat. A homemade bland diet is a mix of 2/3 boiled, shredded white chicken and 1/3 boiled, plain, white rice. You can mix in low salt chicken broth or warm water to make the food softer, more palatable and easier to eat and swallow.
But she really needs to see her veterinarian as soon as possible for another exam and testing.
Please let me know if you have any further questions.