Where problems do arise, they should be dealt with promptly and in an open manner. Sometimes a problem to one party may simply be caused by a misunderstanding on the part of the other.
For example, you may prefer to have a delivery on a Monday and this is attracting a delivery charge. This may because the supplier will need to send out a van specifically as they do not normally make deliveries to your area on a Monday. Having discussed the problem, you may decide that you can take delivery on a Tuesday when there is a van in the area. This will save you the additional delivery charge and make delivery scheduling easier for the supplier.
School / MAT members - the information on this page aligns with the following ISBL Professional Standards: 3.45, 3.46, 3.47, 3.48