Oncidium roots look weired

[Natalie rose]

So I got an ocdium orchid for the first time and it’s been difficult. When I got it the bulbs were shriveled and the leaves were a tellowish green with small black dots on a few of the leaves. The roots were like spaghetti noodles that were white and looks dehydrated. So about three moths later the bulbs are still shriveled the leaves are still droopy, and the roots are still int e same condition except some of the roots near the surface have black tips. And when I pulled on it to see if it was mushy the roots came off like a shell. And all that was left was a white strings that looked like a hair. At one point there was three new leaves growing but then they stopped for some reason. So if you have any advice on what I should do are any tips please let me know. Thanks