i ordered a pair of acs sleeves for my ie8's. because i live in switzerland i had to source out a private audiologist so i couldn't use the voucher included in the price for uk buyers. nevertheless the whole procedure was painless, quick and inexpensive.
i did have a small problem with them because altho they were very friendly, helpful and communicative, they still managed to send me the wrong color iem's. to there credit they did refund me the costs of getting the sleeves colored. also i asked them to rush the job as i am going on a month long trip and wanted to bring them with me and they were very helpful with that. they sent me the sleeves next day delivery.
if you have any issues with acs, i think it would be best for you to communicate directly with them. i have no doubt that they will try to facilitate your concerns as best they can. hope it works out for you as they have made a few head-fi'ers quite happy with their products. take a look at this thread for more reflections:
REVIEW: ACS custom tips + SENNHEISER IE8