Bad service

This I regarding vehicle finance we are been sent sms's saying one amount and when I call or request statements it shows something different so I did enquire about this and they say that the sms's are without interest and statements are with interest and this is absolutely misleading this is my dad's account and he's 60 he does not understand all of this all he thinks is according to his sms's that us what he owes I requested for correct information to be sent or nothing at all but they are still misleading so now we want to be paying according to these sms's that are sent we want to settle the account and l want a settlement according to the sms's sent my next step is the ombudsman for financial services