If the vivo mobile phone needs to be repaired during the warranty period, an official invoice certificate is required. The after-sales service of most brand manufacturers needs to provide free warranty on the basis of the warranty form or invoice provided by users. Beyond the scope of warranty or unable to provide invoices, a certain maintenance fee will be charged. Some merchants verbally promise that they can guarantee their products without invoices, but many warranty forms are not complete enough and the dealers have not signed them, so it is impossible to prove that consumers' household appliances were purchased from normal channels during maintenance, which will bring unnecessary trouble to maintenance.

When consumers buy mobile phones, they should ask retailers for two kinds of bills. One is the invoice, which must indicate the fuselage number, battery factory serial number, product trademark and model. The second is the "Three Guarantees" voucher stamped with the seller's seal, including the relevant information of the mobile phone, the seller and the buyer, especially the maintenance records. Because once the mobile phone has a performance failure, it can't be used normally after two repairs. If there is a maintenance record, the seller shall replace the same mobile phone for the consumer free of charge.