MSC Cruises complaint: Regarding your all inclusive drinks package

We booked our cruise for 4 people on the MSC Europa sailing on the 11323 for 7 nights from Dubai
we had paid for a drinks package prior to sailing
the 2 couples the women do not alcohol but as our husband do we had to pay for the alcohol package for all 4 of us
To our dismay the only sugar free drinks on the ship was diet coke which we do not like
Hence we could not drink any mocktails and as we are both diabetics we have to have sugar free drinks
It was a total waste of money as our husbands did not consume anything near the amount of alcoholic drinks
We only drank water and soda water
I have done over 20 cruises this was the first MSC cruise and I have never known any cruise ship that does not offer only sugar free coke
I did complain to the beverage manager but he advised me to contact you on our return
I do look forward to hearing your response as this did totally ruin our holiday