I currently have a sum up for my small business and it is terrible, first time it worked for a while then started having signal issues, had to walk it round the shop then up the street, then it stopped working. Sum up sent a replacement, which had a fault on it and never worked. Sum up sent out a third replacement, which does occasionally work but very rarely. Really need a card reader but I've already spent £79 for the sum up, can anyone recommend an affordable but reliable card reader? Thank you