You do need to contact Customer Service. They will cancel the so-called BTM part and afterwards you can  place your bus scubscription on your card. Remember that you need balance for bus, tram and metro that are not covered with your bus subcription. Your train subscription does nog change. 

The invoice cannot be collected from a ticket machine. You will need to register at Mijn NS. There is no need to cancel Weekend vrij.

In general it is wise to use two separate chipcards, one for the bus subscription and one for Flex with the NS Flex subscription. It is a lot of hassle to do it the way as written above, and confusing as well.

yesterday some guys from customer service send me to ticket ov machine 2 times

the point is, he is telling me that he cant remove the BTM till i dont collect my invoice..

He tellme i need to go to the machine , So i was trying to do it from the machine , but it doesnt work …

Customer service is not working well , i have spend 4 days in a no sense chat conversation , getting new agents every hour and i need to repeat the same again and again..

And the telephone number is impossible , cos always they are busy 

Now i am trying from 7am on the chat again ,,, and i dindt get any agent attention..

Also twitter is not working

Get a new personal ov-chipcard and put the bus subscription on it. It is wise wise, considering your experiences. Customer Service is very busy.

https://www.ov-chipkaart.nl/purchase-an-ov-chipkaart/apply-for-personal-ov-chipkaart.htm

yes but for  a new OV chip card i need to pay extra 20€ and wait 5 days … i need to travel this friday 

What Customer Service probably means is that you need to confirm the susbscription change at a machine (station, supermarkt). Choose ‘Bestelling ophalen’ (pick up order).