Let your customer know that the number is the CanadaPost invoice for the postage purchased. Then go into some bumpf about your policy of shipping within XX hours/days. Tell him you have checked his paperwork and the item went out on Sept XX and should in your experience arrive within 20 business days. Tell him you have put his paperwork into your BF file for Oct.XX. and then, if you have heard nothing by the day before that, get back in touch.
Since you have sent the item, your job is to reassure your customer.
Small Packet is also insured automatically by Canada Post. The invoice number is also the insurance number. Let your customer know that the item is insured, this is also very reassuring, even though the insurance protects you not him. Small Packet is not Delivery Confirmed.
The 25% discount is not on SP shipping it is on Expedited shipping, which is Delivery Confirmed. I agree the wording used by PP is confusing, but most US sellers only purchase Delivery Confirmation. Tracking is also possible but is very expensive with USPS.
Delivery Confirmation is not tracking. The DC number may be accidentally scanned from time to time along its travels, but neither you nor the customer can count on it.
Again you have to reassure your customer. He can see the DC on canadapost.ca and also on UPS.com. Let him know that this shows it is on its way, but that his letter carrier will only scan it when he has it in his hands, at best a few minutes before he puts it in the mail box.
BTW, some carriers will scan in the truck, discover the receiver is not home, drop a pickup slip (which naturally is immediately eaten by the dog) and returns the parcel to the Post Office. This is also useful information for your customer.
Well this so called registration number which in every respect is a tracking number has the same number configuration as a tracking number, looks like a tracking number, smells like a tracking number, and is called a tracking number on the PayPal site.
You can make this confusion work for you too. Since I have been inclluding the invoice number in my feedback, my honest customers are reassured that the parcel has been sent, and I believe a few sketchey buyers have decided not to try anything since there appears to be a DC number .