Support and the way they treat their customers.
First of all, it's super hard to contact their support I submitted 3 tickets and it took 3 days to finally get someone to respond.
We are leasing the office space from the company that was using Bill.com to accept payments for their bills, therefore we were forced to use bill.com to pay our monthly office rent. Everything was ok... Then the company we paid for the rent switched to using Xero since it doesn't really make sent to pay ridiculous amounts for bill.com.
Anyway... for us, it was even better because now we didn't need to pay bill.com subscription fees to just pay for the rent (simple ACH). So we went ahead and canceled our subscription with bill.com in August.
A few months later (in October) I noticed that they were still charging our credit card and as I mentioned above it took 3 days to get someone to finally respond to our support tickets.
What I asked for was simply refund the last 3 charges (Oct, Sept, Aug) and close our account simply because their system failed to cancel it in the first attempt. Simple right? Nope, not with Bill.com
They had someone to call me and tried to explain that they didn't see my first request to cancel and if I didn't use their service since August it was my problem and that evidence that I didn't even log in to their service for 3 months is not enough for them to refund.
So my advice to you, if you ever thought to use bill.com for your business, please stay away. There are tons of great innovative companies on planet Earth who would love to do a business with you and will value you as a customer!