Tier 2 visa wrong application fee given

Hi.i applied for tier 2 visa .my employer gave me cos and used 2139 job code. I checked on shortage occupation and the code was therr, so i checked shortage occupation in the application and paid the shortage occupation visa fees whereas the job i am offered in not the one covers under shortage occupation as only cyber security specialist is covered under 2139 for shortage occupation. All other job codes under 2139 are not considered as shortage occupation. I made this mistake and believe the home office could pick this mistake.i am advised that i can write to them and send a postal order for the difference in fees amount but some solicitors advised otherwise and said they dont accept the payments like this and i have to reapply and lose the fees already paid.i paid for my dependents too so not a small amount.can someone advise?

I cannot do the new application as today is the last day of my current visa.

Did you apply from within the UK?

If so, the chances of the Caseworker writing to you for additional payment are very high.
A person who made a similar mistake got the following email from the caseworker. hopefully, you will get the same. ( The below case is a 5 year Tier2, so please don't come up with figures and calculations. )

"Dear XXX
Thank you for your application for leave to remain within the United Kingdom.
While you have paid £1,747.20 for your application and enrolment, this, unfortunately, is not enough to process your application.
The reason for this is as your spouse XXX has paid for an over 3 years visa with her occupation not being on the shortage occupation list, you are required to pay the same amount.
The total amount you need to pay is £2,227.20. This is a difference of £480 that you need to pay.
Please fill in the attached form and send it back to us as soon as possible.
As we have had to make this request, we are unfortunately unable to fulfill the service level agreement of 24 hours."

Hi.Yes i applied from within UK

And thank you very much for your kind reply.