Had the same case with TS, MOP 158 turned into MOP 98, spotify not included anymore.
Called CS, they said MOP158 shown initially in apps was just a header for 5GB data...wth.

Right now i'm seeing my data in maxis apps as follow:
1)Free 3GB (45 days)
2)Free 4GB monthly ( I suppose this bundle together with 1GB previously)
3)MaxisOne 5GB

Yea, you're right, 4GB start date on 21st April, guess next month I will not have this.
Argued that I was offered MOP158 with RM90 rebate and was downgraded to MOP98 without my consent, CS agreed but now keep insist that the new plan will be leaving everything unchanged. On Spotify, she say I was not offer previous month also..zz