Same here today, tried to access the page to unsubscribe,

Did all
1) Use mobile data instead of wifi
2) Tried using normal browser instead of chrome to m.maxis.com.my/spotify and got to redirected to the normal spotify page
3) Tried using chrome incognito instead to m.maxis.com.my/spotify and same thing redirected to the normal spotify page

Called customer service, twice:
1) The first one asking me to unsubscribe using the method above
2) The second one asking me to login to spotify and unsubscribe there

I didnt bother to call for the third time... i doubt that they know what are they talking about. So, until now, no luck in unsubscribing spotify