2 different watch, different amount with same code

Avon advertised 2 watched pink for R379 and blue for R399, my first order inv ***5 my customer ordered a pink watch with code ***, delivery came and they delivered a blue watch for R399, went to do a sense check avon has 2 different watched different colour different price for the same code, who is now liable to pay the balance of R379 while they charged me R399 and my customer opted for watch for R379 pink one, my second order I ordered the blue one for R399 same code as pink watch - can avon credit for the first watch because error is not on my side and if I do not pay them they will be quick to charge me for late payment, i sent an email but i am so understood and its very frustrating