Spam company - don't give this company your phone number

I bought a gift in Swarovski Clearwater store yesterday. The salesman asked for my mobile number. I checked 3 times with him that it would not be used for marketing or SMS purposes. He assured me it would not 3 times. He said he needed it for warranty purposes. Today I have received a marketing/ spam message from Swarovski Not only did I not consent to receiving SMS but also I specifically said I did not consent to receiving SMS from them. Additionally there is no option to unsubscribe.