You can cancel the order in OmaElisa if the order has not left and place a new order:

OmaElisa/Product and orders/Orders

Or:

Peru tilaus OmaElisassa 

Goes directly to your orders

And:

https://elisa.fi/asiakaspalvelu/english/orders-deliveries-and-cancellations/

Consumer cansellation right of remote sales.

You have a right to cancel your order placed via remote sales for 14 days after the order confirmation or the device has been delivered. You can find device and service specific cancellation instructions below.

As Kimblez said, you can cancel the order from the OmaElisa. I would like to add, that if you paid the product already, you should be able to enter your Bank Account Number to OmaElisa for returning the money. 

Welcome to OmaYhteisö ​@nataliagromova !