[VIC, NSW] AmEx Offer: Spend $100 or More at Tango Energy, Get $25 Back, up to 3 Uses

DETAILS
Save the offer to your eligible Card and spend $100 or more, in one or more transactions, online or via phone at Tango Energy by 31/01/2022 to receive a $25 credit, up to 3 times. Exclusions apply.

OFFER TERMS
Offer is limited to $75 credit per Card to which the offer is saved and only spend on this Card counts towards the Offer.
Excludes transactions where you do not spend directly with your Card to which the offer is saved, online at tangoenergy.com or via phone to Tango Energy.
Excludes transactions made through a third party establishment or payment processor.
Credit is not redeemable for cash or other payment form.
Credit should appear on your billing statement within 5 business days from qualifying spend but may take up to 90 days from the offer end date.
Credit will not be applied to your Card Account if your Card has been suspended or cancelled.
Credit may be reversed if your qualifying purchase is refunded or cancelled.

Im not sure on their rates and if Tango still have a referral program?
so compare at https://www.tangoenergy.com/energyplans?marketsegment=Home&p…
Does anyone know if you over pay your Tango account with an Amex card will they refund the credit balance back into your bank savings account or they will only refund it back on the Amex card?
Also note changing energy provider will also most likely involve another credit check.