Nokia 5233
Device Problem

I purchased Nokia 5233 (imei no. 352000049512225) from Nokia Priority dealer, Deep Market, Ashok Vihar Delhi on 23/07/10

Every time I used the volume rocker buttons to increase or decrease volume the device produce crackling sound and slow down the music fow few seconds. What may be the problem?

I am using a 4GB memeory card from SANDISK original. I have already used this memory card in my Nokia 6303 for about one year and it never shown any problem like this.

Please tell me what to do?

Is it device problem or software problem?

Please answer to my queries ASAP.