master package question

hello so around 4 months ago i had a csgo subscription on 3 months. after about 1-2 weeks of this i decided to buy the mastare package for 3 months. I realised that my csgo subscription only went back up to 90 days instead of getting 90 days plus what i had. I was wondering is this how its supose to be or is it possible to get back those days? (didnt ask earlier cause i thought i might have gotten the extra days added after these 90days). Just wondering
thanks

Pm zim with proof of payment etc...