MISHAWAKA — The merger between MFB and Mutual Bank became official Friday. But the changeover hasn't been smooth for everyone.

Officials at Mutual Bank say their phone lines have been jammed with customers calling about their debit and credit cards, checks, and accounts since the merger went through.

Many customers tried using their debit and credit cards, only to find out they were declined. That wasn't the only problem. Delivery of new cards was also delayed.

For some customers though, the changeover has been a pleasant one.

“Just some minor changes that's all,” said Mutual Bank customer Lisa Bartkowiak said. “It's been great.”

“We’ve experienced no problems with the accounts or anything,” agreed customer Bill Maines.

For other customers, days after the merger, business at the bank left them frustrated and full of questions.

The merger has changed online banking, introduced new credit and debit cards, and forced customers to get brand new bank account numbers.

“They changed their account numbers and all of this happened so fast,” said Mutual Bank customer Heather Hahn. “They gave us the letter one day, like Monday, and then by Friday I got my debit card.”

“It's kind of embarrassing, because you know you have money in your account and you go to use it, it gets declined,” said customer Jennifer North. “It’s like why did it decline? They told me I could use it!”

Chuck Viater, Regional President of Mutual Bank, said a lot of confusion occurred during the mailing process.

“I think a lot of people saw that and didn't realize it was from our new organization in anticipation of this weekend coming,” said Viater. “And they didn't recognize they needed to hold on to that.”

The bank says it mailed notices in June. But as of Wednesday some customers still don't have access to their cards or money.

“If it didn't go as they had hoped, then it didn't go as we had hoped,” said Viater.

“If I don't receive anything by this week, I think I am going to switch banks because it's getting frustrating,” said North.

With fears of losing customers, Mutual said its operators and tellers will do their best to help make this a smooth transition.

The bank is encouraging customers to call their Customer Support Center at 1-800-382-6031 or visit one of their branches.