Three men ripped a fitting off the wall before stealing over £3,000 worth of stock from a Lincoln branch of Carphone Warehouse.
The three men, believed to be in their 20s-30s, and with European accents, entered the High Street store on Wednesday, May 16 and the incident was reported to police at 1.16pm.
A member of staff shouted at the thieves, who used aggressive language in response before making off with phones worth £3,100.
All the phones will be missing sim trays as this is a usual deterrent used by the company.
Anyone with any information should contact police on 101 quoting incident number 212 of May 16.