please I need to unlock my blaupunkt type CAR 300 (D)?

I fixed my battery car and lost the code of the audio,cassette players,I entered the wrong code and the screen shows 7safe. how to return to ---- digit on the screen,and i forgot the code,I remenber that it was 3 same number and only one is different like:3353,4434,3433,3533 ...... please how to fix it. my audio,cassette is a blaupunkt type:CAR 300 (D) 2F2 made in malaysia No.: 90 532 620 GM 0300S2263340 FD572 7 645 852 520