I’ve found that most good affiliate programs would agree to paying me when I had not met the minimum if I asked politely and it was just on occasion, not something I requested regularly. However, Vegas Affiliates was the only one I’ve ever asked that flat out refused.
Most affiliate programs hold what you make in a month, regardless of what happens the following months. So if you had a minimum $250 you needed to be paid for your earnings and made $150 in March and in May had a negative $300 and in June had $100 positive… I would expect to be paid $250 in July for my March and June earnings. The positive from March should not be eaten up from a negative result the following month(s).