Bad service

They phoned me, I ordered the 2 cartridges from them, delivered on the 16/01/20. The cartridges don't work, If I phone them on the number provided on the invoice, no one answers... ?? Luckily they phoned to ask about the cartridges... I informed the to come and collect their cartridges that doesn't work... up till today the 11/02/2020, no answer when I phone... and still not collected. If they phone it is always from an anonymous number... why don't they answer their phones??? do you hide something??