Very Poor Service

I took my sons paintball gun in for repairs on a Saturday and was told it would be ready the next Tuesday. On the Monday they contacted me to say they news to order a part and it should be ready by the Tuesday. After me following up they informed me they hadn't received the part. This carried on the rest of the week and when I went in on the following Saturday to complain they said that if I was unhappy with their services, I could take my gun elsewhere. It is now over a week and still no feedback from them.