I noticed a duplicate post you bought the V20. Please stick to one, the other will be removed. The V20 was on sale for 1/2 price in May. The bill credits on the 1/2 price will post in 2-3 bills and include back credits. You might have had 2 bills since purchase, but not 3. See the promotion here.
https://forums.att.com/t5/Android/LG-G6-and-V20-half-price/m-p/5138126