Purchased some snacks in flight and the attendant said the total was $16 but charged $26 to my card. Frontier CS says they can't do anything as they can't see the transactions. Only option is to contest it with Credit card company? Any advice?

I was recently on a flight and a passenger asked for a receipt but was told they don't receive a receipt and I feel like buying a coffee once in a while but I won't if I can't have a receipt.

You can get a receipt for your purchase so you can see what they charged you for: https://faq.flyfrontier.com/help/in-flight-receipt
This should be an easy credit card dispute to win if RetailinMotion or Frontier won't help you.

Thank you very much for the link. I am surprised the customer support person didn't point me to this. Found the receipt and the flight attendant even entered the wrong items I purchased. Instead of $3 apple juice I got for my kid (along with my bud light and his pop tart), he entered something from Bailey for $9 and also I don't understand how a total of $23 became $26. This is so messed up. I should have been more careful to ask each individual price and total more clearly instead of just handing out the card
Product Price(USD) Qty Amt
--------------------------------
Bailey's I 9.00 1 9.00
Bud Light 9.00 1 9.00
Pop Tart B 5.00 1 5.00
--------------------------------
Total USD 23.00
--------------------------------
Credit Card USD 26.00

Maybe the kiddo actually got a Baileys? My guess is the $3 difference was a tip but that's just a guess.

Annoying that there is a section to leave a tip! Remember when food on airplanes was distributed at no cost?

it still is on some flights on some airlines. Of course, average fares on those airlines are higher than on Frontier so it's more accurate to say the cost of the food is bundled in to the ticket cost. There are few free meals in life.