Actually, the 11th is too early. Wholesale terms generally relate to the POSTMARK date, not the date received. As long as a check is postmarked by the 10th, or the next postal work day if they are not working the 10th, it is considered timely. The same with discounted terms, such as 2% 10th Prox, Net 25th. A postmark on the 10th will qualify for the discount.

Calling before the 20th will only cause problems. Depending on previous history with the account, I'd wait as long as the 25th. Certainly before you print your next statement.

Keep in mind that once accounts get to 90 days you hardly ever collect them. There are 2 distinct ways of handling in-house accounts - Easy Open & Hard Collection or Hard to Open & Little Collection Needed. Dealing with contractors, you have to understand they sometimes get strung out by their main contractor or builder and you've got to roll with them or lose them.