How do I buy with silver if the shop wont accept it?

Silver is a commodity trading in the market like any other good or service. Your silver is insurance. It's a long term store of value. To quote Warren Buffet. 'In the short run it is a voting machine, in the long run it is a weighing machine'. There has never not been a market for silver. The same for gold, apples and guitars. Whatever your shop will take, will be tradable for silver.