I’ve being going over their TOS for paying with bitcoin, and there are a couple of things to point out:

-   Not all products are payable with bitcoin. Only those for which payment is available with bitcoin will be selectable as a means of payment.

-   If you underpay, purchase will be aborted, and you need to contact Bitpay for a refund.

-   If you overpay, the purchase will go through, but you will need to contact Bitpay to get back the amount that exceeded the price.

-   If you give back a product, refund will be in fiat (pesos)

See: https://www.elektra.com.mx/terminos-y-condiciones-bitcoin (in Spanish -> Google translating the link does not seem to render a visible translation).


As to the TOS for the Bitcoin promotion itself, I’d point out the following:

-   Purchase must be in the range of 5K pesos (240 USD aprox.) to 57K pesos (2750 USD aprox.)

-   The promotion has an allocated fund of 1M Pesos (a bit over 48K$)

See: https://www.elektra.com.mx/terminos-de-promociones (In Spanish)