When the buyer tries to make a payment, the error "The data you have provided can not be processed by Ingenico Payment Services" occurs.
Check if the points from this FAQ article resolve the issue.
This can also happen when the buyer has entered too long data in one of the checkout fields. See the Parameter Cookbook for a list of maximum lengths.
Usually, the buyer should get a notification directly in the checkout if some data is too long. There should be a red arrow pointing to the field containing invalid data.
If this doesn't work right (e.g. because the checkout was modified), you could implement max-length for the various checkout fields, corresponding to the lengths shown in the Parameter Cookbook.