What is the start of the contract date that MOHRE take into consideration?

Good morning,

The company made me redundant one day before completing the 6 months probation period.

As per the contract of MOHRE, the start date is 18 Oct but they asked me to sign a letter late that the start date changed to the 27th of Oct and I had to sign the letter.

The letter is not even signed by some IT guy in the office. I feel they knew what they are doing hence the new letter to change the new start date.

Can I complain about that?

Is the letter recognized by MoHRE or the date on the contract is the one?

Thank you