Neumeric value for contact number and price field

Good day.
Currently i have a problem with the db key for the price and contact number fields.
When a listing is created, the user can enter any value from a-z and special characters.
I tried to use the db key price [price] PRICE [PRICE] and the same for the contact number.
in the support forum I found a question similar to mine, but in the reply, they mention to select numeric in the set-up fields but in my set-up field I do not have a selection of numeric values.
Please see attachment.
How can i solve this problem?
thank you.
Charl.