Something similar happened to my husband about 20 years ago. He has ssdi, and can only work a certain amount of hours a month. He tried one month to see if he could do full time work. Nope, impossible.
And so gets kicked off ssdi, and had to fight to get back on it. And they charged him for being on it...by deducting the money he now 'owed' them from the new ssdi. It was stupid.
The laws in place are also why my husband is husband in name only. If we ever actually got married, goodbye everything keeping him alive! It sucks.