Background: We take advantage of grandma care for our child care needs but there are times I need to hire a nanny for when grandma isn't available. At the end of last year, I decided to enroll in FSA dependent care. Now I'm trying to figure out how to get money out of it.

We have hired some part time help.We hired two nannies both worked 2-3 days. Both were each paid less than $2000 so it makes me exempt from paying taxes. I got or will be getting their SS number and we paid them by check.
I need to look into it further. I was not clear when I hired them that I would need to have their SS number. (Ooops! What was I going to do? I needed a nanny and they both ended up being great with the kids. Decided I would figure it out later...)They gave me their SS number but I told them I would look into it before submitting anything. Oh, they know I have this FSA account and I need to show proof of a nanny before I can get any money out. So at the moment, they both plan on using the money under the table (not reporting it). On one hand, I would benefit from using the FSA funds but they would have to report the income. Or I could not use the FSA funds and they get paid under the table. It does seem like being paid under the table is not what they 'should' do but I don't really have a say on how they report income, right? It's not my business, right? I understand if I pay them over $2000, that I become an employer and have to start withholding and paying taxes. I kinda screwed up by not making sure before they started watching my kids.

I think I need to be clear with anyone I hire in the future that I will need their SS # and the government may see this income.

The other issue is I'm quitting my job soon, so I'm pretty sure I have to use up (or claim) the dependent care FSA before I leave. I sort of knew this when I enrolled in FSA, but I thought I could easily use the funds towards any part time nanny or babysitters. I had no idea that I would have to find someone willing to report the income.

Should I talk to a CPA about this? Seems like this is really a tax issue on my nannies end and not really a tax issue on my end since hiring them is not subject to taxes (because I pay them under $2000). https://www.irs.gov/publications/p926/ar02.html

Oh, both are nannies for other families so what I paid them is probably small considering all the jobs they do throughout the year. Do they not report the income they make for all of their other families? Anyway, I know, it's not my problem.

ETA: The other alternative is the pay grandma, but she would have to to report it. And therefore, I would have to pay and withhold taxes. I guess I don't know if some of her visits can be considered family visits. She is and isn't working for us. She's spending time with our kids. I don't know know where the line is. She doesn't need the income since she is retired. We pay for things for her but it's more like gifts to show our appreciation for watching our kids.
Although, looking at the IRS document, spouses & parents are exempt from employment taxes.