Entitled to redeem

[Xinfu]

My terms and conditions draft:

1.This voucher is only entitled to redeem 8 pieces of Delicate Cake priced at $4 at Max's Cake.
2. This voucher cannot be exchangeable for cash.
3.This offer cannot be used in conjunction with Max's Cake Coupon.
4. Only original voucher is accepted.

Are my sentences correct and natural English?

[Rusty]

Numbers 1 and 2 are OK, but I would personally not choose 'entitled to redeem' and 'cannot be exchangeable'.
Number 3 is very natural English.
Number 4 needs an article.

[poli]

My terms and conditions draft:

1.This voucher is only entitled to redeem 8 pieces of Delicate Cake priced at $4 at Max's Cake.
2. This voucher cannot be exchangeable for cash.:bad:
3.This offer cannot be used in conjunction with Max's Cake Coupon.
4. Only original voucher is accepted.

Are my sentences correct and natural English?
1) With this voucher you are entitled to redeem 8.....
2)This voucher cannot be exchanged for cash.

[Xinfu]

Thank you~