What Causes Vaginal Spotting After Taking Marvelon To Delay Periods?

Hellow, My last period was supposed to come on 6 june, but starting 26 may i start to take marvelon pills to postpone my period formone whole month ( month of fasting ), around the expected day of my period, i started to see some brown to pink spottings so i started to take 2 pills of marvelon twice a day..spotting persists even until now even its more frequent and more red than usual..i consulted my gyneco he said to take duphaston twice a day, coz i still want to postpone for another 10 days.. Please i need a second opiniom..and to note that im have sterile and im taking aldactone prescriped by a vascular dr to avoid water retention.. Will duphaston help to delay my period for another 10 days, any counter effects if its taken with aldactone?? Plz advise