Changing dates on a request keeps changing price!!

[Ingrid18]

Am new to hosting and am having trouble with sorting out a request to book.

C made a request to book for 10 days and I replied that he needed to book either 1 or 2 weeks

C tried to change his booking dates and couldnt so he asked me to do something

I was able to change the dates to 2 weeks using special offer but when I sent out the offer the price remained the same as if booking for 10 days. This was not my intention.

I then withdrew the special offer and told C what the price was for 2 weeks but on his request to book the old dates and related price still appear.

How can I send him an offer with 2 weeks at the full price

OR

How can C change the dates and have them reflected in the price?

Any help more than welcome !! Thanks guys!!

I.