I also like to take this opportunity to introduce my co-worker, Mr. Talley Qi (technical supervisor of Grafmac Company), who will take over aftersales service support matter.
You can reach him via below contact info. (He is my master and shall do more professional technical advice to you than I did. )
Mr. Talley Qi, contact number: +86 15995607397
Email: talley@grafmac.com
wechat account: talleyqi
For sales related matter, you can contact Erin (erin@grafmac.com) as usual or contact Mr. Ryan Chan directly.
I sincerely wish you well and all the success in your future endeavors.