Delivery of parcel did not arrive and they refuse to refund my money.

I ordered a phone from gearbest (for my cousin's birthday) in August knowing it will come in October because of their estimated date. almost 3 weeks after time of order they contacted me letting me know the phone is not in stock but they do have stock now and would like to proceed with the process. I agreed because now the phone supposed come in November, which is fine because my cousins birthday is 1 December 2017. 30 November 2017 came still never received anything.. 31 December 2017 came, still never received anything.. so I contacted them now this month (January 2018) and they tell me that i should have contacted them, for a refund, with-in 3 months after i ordered the phone. But then i let them know that the estimated date was already 3 months from the date of order but they do not reply!