The Latics are keen to sign the Omani goalkeeper permanently after he impressed on loan at DW Stadium last season but Whelan is unhappy with how the Trotters are acting in regards to the transfer.
"We've made our offer, and we're sitting on the fence at the moment," said Whelan.
"They're trying to get more money out of us, but we've told them straight, we're not paying any more money.
"We saw our first bid turned down, which we thought we might, and our second offer remains on the table.
"It's our fullest and final offer. The offer is what we were quoted for last summer - £3million."