Talks between Man United and Brentford have been at an impasse for the past few weeks after the 20-time champions had two offers rejected.
Mbeumo, 25, is understood to have his heart set on a move to Old Trafford and has rejected advances from fellow Premier League giants Tottenham and Newcastle.
According to The Guardian, any potential deal has hit a stumbling block, however, and Brentford have now increased their asking price to £70 million.
That’s where Ratcliffe has stepped in, and he is adamant the club will not overpay for the Cameroon international.
United have struggled to make any real headway in the summer transfer window as they are in desperate need of selling before they can buy.
Marcus Rashford, Alejandro Garnacho, Jadon Sancho, and Antony are all expected to leave, but no concrete offers have come in.