As a regular AC Models customer, I can also confirm they are still open and working hard to support our hobby, both by having a retail premises and also supporting mail order customers via Ebay and Amazon shops. The High Street shop is currently operating with revised opening hours (Tuesday, Friday and Saturday from 10am-4pm) and customer numbers are restricted to allow social distancing, which usually means a member of staff has to act as "doorman" to ensure this is adhered to, which may result in phone calls being unanswered if staff are otherwise engaged. They have also been unable to agree terms with the landlord to extend the lease on their adjacent smaller shop after a hefty rent hike, so stocks of R/C models, some spares and wargaming items are currently unavailable as that premises is currently being refurbished ready to be returned to it's owner as per the terms of the lease. However, I believe there are future plans to expand to the first floor of number 9, but this will all take time, effort and lots of money, which is not always easy for a family run business in the middle of a pandemic.
Judging by the number of parcels awaiting dispatch that I saw there on my last visit, NGM's statement that they are "Taking money but not shipping ?" does not appear to be the justified. As previously suggested, a phone call to the shop number during their opening hours is probably the best way to get in touch.