Default on internet installment loan with BalanceCredit

Hello. I have an installment loan with BalanceCredit.com that I signed up for on the internet. I had some illness and got behind. I tried and tried to work out payment arrangements with them and they just would not budge. Now I have received a notice to accelerate the loan from them. The notice came via email from SunUp Financial. Apparently, they own BalanceCredit. The odd thing is any emails about this account I have received prior to this came from BalanceCredit. I have not received anything from SunUp before. For some reason, this email from them went into my spam email. I only saw it when I went into look for an email resetting a password for another site that said to check my spam email for the password reset. I found I got my first notice from SunUp in my spam email in October. Now the notice to accelerate comes one month later, also in my spam email. The original loan was for $250. They now say I owe $892.00. I have never received a notice to accelerate before. Are they going to sue me right away or will I be turned over to a collection agency? Can they garnish my wages without filing a lawsuit against me? Should I just start making payments online even after receiving this notice to accelerate? Up to now, they would not accept smaller payments when I talked to them but I might still be able to make payments online without talking to their collection department. I am a nervous wreck!