Huawei — deceived by huawei

Reading about the new Huawei cellphones specifications, two weeks ago, I went to a Huawei sell center in Tehran to buy a new cell phone.
The person who were in charge of that sell center, told me that if you buy Nova 2 Plus, we will give you a gift card that worth 100000 toman. In addition to that, he said that this phone is guaranteed for 18 months; hence, I bought Nova 2 Plus. After I paid the total price, I asked about the gift card and they told me that you should go and we will call you later. The week after that, they called me and I went to get my card but not only they didn't gave me the gift card, but also they behaved very bad and called me a lier.
Being disappointed from Huawei sell center services, I called the Huawei customer support. Although the shop that I bought my cell phone from was the Official Huawei Sell Center, the customer supports told me that they will not do anything to help me.
Being unable to do anything, I went to the sell center again, and not only they didn't gave me the gift card, but also I found that this phone is guaranteed just for 12 months, and they have deceived me from the first place.
I feel that I placed far too much trust in Huawei. Your staff in Iran are rude, they coarse your customers, they tell lies to sell, and after that when we call the customers support, they say that they will not do anything about it.
All in all, I lost my trust in Huawei, and sending you this email is my last shot. I hope there is still a little morality left in Huawei core company.