Urgent Help Needed | Wrong IHS Payment made for Tier 2 General Visa 3 years

Hi All

I am looking for urgent help from the experienced forum members.

I submitted my General Visa Tier 2 Application today. When directed for IHS payment, it asked me if I am joining someone and I filled yes as my wife is already in UK.

Hence, it seems it took me as her dependent and calculated IHS fee based on her visa expiry which is in 2020 where as my COS is till 2021. I paid 39800 for the IHS and this seems appprox £400 instead of £600.

How can I pay the difference or get this information edited. Should I have mentioned I am not joining anyone ?

I have submitted my online application and have the appointment on Tuesday.

Any help is much appreciated.