Sub par products and no after sale service

In September I bought an inverter and lithium battery from them. It's now January , I've already had to send back the original inverter and buy a new one and today the battery also stopped holding a charge, this is a lithium battery with a 1500 charge cycle. The inverter runs a router a fibre ont and a laptop. 4 Months and nothing is working. When you call them, all you get it, well not there problem, take it to mustek. Avoid them, they only want the money