Originally Posted by catocony
Why would Visa deduct miles? If you return something it's a credit and goes on your account, and the miles are paid out as of the billing date. Thus, you have the equivelent of mileage credits as well. If you spend $1,100 the following month, your end-of-month statement will be for a payment of $100, and you will receive 100 United miles. It all stays current.
I have seen statements from VISA with
negative mileages contributing towards MP.
Mainly, if you spent $5000 last month and your MP account was credited 5000 miles by visa and subsequently made a refund of $3000 in the following month, VISA will
deduct 3000 miles in next statement.
Of course, if you also spent $2000 in the following month, then VISA deducts 1000 miles as difference, assuming that every dollar earns 1 mile (to simplify the argument).