British Gas complaint: Bill higher than expected

Dear sir Madam
I was puzzled to find a very High Bill on return from my Holidays.
I left my home on 13th December 2022 and returned on 21st January 2023.
So I was not home for almost 6 weeks. The electric Bill I found was from 6th December 2022 to 6th January 2023. It was £252.93 for 6 days I was in the house.
And on 6th February 2023, I got a Bill of £ 252.75 for the 16 days I was home.
Making that a cost of £505.68 for only 24 days I was in the house.
I have a feeling my electricity usage is miscalculated.
I beg you please try to see whether the meter is working properly.
I am not able to afford a specialist engineer.
The meter reading today at 15.37 is 02784kwh. this is also strange because your staff told me the meter reading for my smart meter was 600kwh.
so which is right?
I will be very grateful for your assistance.
Regards
Maria Batesaki