Nokia 5800 xpress music
Problem while sending sms

I am using 5800 xpress music for last 6 months and did`nt find any major problems. The only problem with my phone is that whenever i sending a sms of below 160 charater its taking 3 pages while sending and its cost 3 sms charges for one sms and it also shows 3 page sms to the receiver.

Could anyone help me plz...