Ipsos had a glitch at the beginning of the year. I got paid the last week of last year, then nothing for the first 3 weeks of this year, even though I had shops received, edited and approved for pay. I wrote polite letters, then less polite letters, and then I was told that received, edited and graded means nothing and they'll pay me when it's approved for payment. Then a few hours later I received one payment, and the following day I received the other. And I was told that it was a glitch in their system and the problem has been corrected.
The first one they said it was a glitch in the client's software, the second, because it's a different client, they had to make up a different excuse. I've been keeping track, and they haven't missed any more payments.
That was a little strange getting paid on Sunday. Ipsos pays on Tuesday, Paypal usually notifies me Monday evening, and I transfer it Monday night and it's in my bank on Tuesday morning.