composition or regular

I had opted for Composition , but had to opt out because I have rental income also. I was in Composition from 01/07 to 09/10. I had not filed any return or paid tax till then. On 10/10, when I withdrew from Composition, considering my self under regular I paid tax and filed GSTR3B for July/Aug/Sept. Now the portal says I should be filing GSTR4 and pay tax accordingly.Do I get refund of taxes paid earlier?