Payments in installments (e.g., when using Oney or an equivalent service) are divided into several transactions, each of which will be analyzed as a separate transaction.
It depends on the conditions of the offer:
If the offer has a minimum purchase requirement, each of the transactions will have to be greater than the minimum purchase to meet the conditions of the offer. For example, if there is a minimum purchase of €100, but you pay €150 in 3 installments, it won't work because you will be charged €50 three times.
If it is an offer for people who have never purchased at the store, only the first transaction will be taken into account by the offer.
If it is an offer for people who have already purchased with the company, all the transactions will be taken into account as soon as each transaction has been charged during the period in which the offer is active.