faq: add entries

content/about-us/faq.md

@@ -59,6 +59,16 @@ You can build a useful ARTIQ system and spend very little money by running the o
 
 This is not a turn-key solution; experience with electronics, FPGA, and software development is required, and you will have to spend some time studying the code, porting it to these boards, writing drivers, and building hardware adapters.
 
+##### Do you have a warranty?
+
+For most products, we offer a 1-year warranty against manufacturing defects.
+
+##### What should I do if I need technical support, or there is a problem with my order?
+
+Please contact us at helpdesk@m-labs.hk.
+
+If you have contacted the helpdesk and your issue cannot be satisfactorily resolved, then contact sb@m-labs.hk or text +852 65873703. Mention your helpdesk ticket number. 
+
 ##### What are your payment terms?
 
 For most established institutions (determined at our discretion), we offer Net 15 and Net 30 terms after delivery. Please enquire from your institutional email address to help us determine your eligibility for these terms.
@@ -85,6 +95,14 @@ Exclusivity is subject to contractual minimum order volumes determined at our di
 
 Some features are currently not available on the mirror site, and you may use a VPN or another circumvention measure of your choice to access these as required.
 
+##### Why are you ignoring my emails?
+
+If you are using the email server of a large institution, be aware that some may silently drop emails sent to .hk email addresses and/or to servers located in Hong Kong.
+
+Try sending your message from your personal address (for example Gmail, Outlook and Yahoo do not block our email system), or to the same email address at the m-labs-intl.com domain (for example, sales@m-labs-intl.com or sb@m-labs-intl.com).
+
+Alternatively, you may use our [contact phone numbers](../office/), which are also registered with several popular messaging apps.
+
 ##### We are a recruitment firm. Can we help you find talent?
  
 No.